quarkus.oidc.auth-server-url is missing in the all configuration guide
**Describe the bug**
`quarkus.oidc.auth-server-url` and other found in https://github.com/quarkusio/quarkus/blob/df5f7d27916db069d2bcc0744ced7e79d2b79584/extensions/oidc-common/runtime/src/main/java/io/quarkus/oidc/common/runtime/OidcCommonConfig.java are missing in the https://quarkus.io/guides/all-config#quarkus-oidc_quarkus-oidc-openid-connect section. 

**Expected behavior**

properties to be listed

**Actual behavior**
properties are not listed

**To Reproduce**

Visit https://quarkus.io/guides/all-config#quarkus-oidc_quarkus-oidc-openid-connect and observe missing properties. 

**Additional context**

I think the generator is not scanning config items from super classes, in this case https://github.com/quarkusio/quarkus/blob/df5f7d27916db069d2bcc0744ced7e79d2b79584/extensions/oidc-common/runtime/src/main/java/io/quarkus/oidc/common/runtime/OidcCommonConfig.java  hence that's why they are not showing. 

/cc @miguelsorianod thanks for spotting this. 

diff --git a/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDoItemFinder.java b/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDoItemFinder.java
index f85409c707e..97133943a78 100644
--- a/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDoItemFinder.java
+++ b/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDoItemFinder.java
@@ -19,7 +19,6 @@
 import static io.quarkus.annotation.processor.generate_doc.DocGeneratorUtil.stringifyType;
 
 import java.io.IOException;
-import java.nio.file.Path;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -63,14 +62,16 @@ class ConfigDoItemFinder {
     private final Properties javaDocProperties;
     private final Map<String, TypeElement> configGroupQualifiedNameToTypeElementMap;
     private final FsMap allConfigurationGroups;
+    private final FsMap allConfigurationRoots;
 
     public ConfigDoItemFinder(Set<ConfigRootInfo> configRoots,
             Map<String, TypeElement> configGroupQualifiedNameToTypeElementMap,
-            Properties javaDocProperties, Path allConfigurationGroupsDir) {
+            Properties javaDocProperties, FsMap allConfigurationGroups, FsMap allConfigurationRoots) {
         this.configRoots = configRoots;
         this.configGroupQualifiedNameToTypeElementMap = configGroupQualifiedNameToTypeElementMap;
         this.javaDocProperties = javaDocProperties;
-        this.allConfigurationGroups = new FsMap(allConfigurationGroupsDir);
+        this.allConfigurationGroups = allConfigurationGroups;
+        this.allConfigurationRoots = allConfigurationRoots;
     }
 
     /**
@@ -97,6 +98,7 @@ ScannedConfigDocsItemHolder findInMemoryConfigurationItems() throws IOException
             final List<ConfigDocItem> configDocItems = recursivelyFindConfigItems(element, rootName, rootName, configPhase,
                     false, sectionLevel, true);
             holder.addConfigRootItems(configRootInfo, configDocItems);
+            allConfigurationRoots.put(configRootInfo.getClazz().toString(), OBJECT_MAPPER.writeValueAsString(configDocItems));
         }
 
         return holder;
@@ -109,6 +111,27 @@ private List<ConfigDocItem> recursivelyFindConfigItems(Element element, String r
             ConfigPhase configPhase, boolean withinAMap, int sectionLevel, boolean generateSeparateConfigGroupDocsFiles)
             throws JsonProcessingException {
         List<ConfigDocItem> configDocItems = new ArrayList<>();
+        TypeElement asTypeElement = (TypeElement) element;
+        TypeMirror superType = asTypeElement.getSuperclass();
+        if (superType.getKind() != TypeKind.NONE) {
+            String key = superType.toString();
+            String rawConfigItems = allConfigurationGroups.get(key);
+            if (rawConfigItems == null) {
+                rawConfigItems = allConfigurationRoots.get(key);
+            }
+            final List<ConfigDocItem> superTypeConfigItems;
+            if (rawConfigItems == null) { // element not yet scanned
+                Element superElement = ((DeclaredType) superType).asElement();
+                superTypeConfigItems = recursivelyFindConfigItems(superElement, rootName, parentName,
+                        configPhase, withinAMap, sectionLevel, generateSeparateConfigGroupDocsFiles);
+            } else {
+                superTypeConfigItems = OBJECT_MAPPER.readValue(rawConfigItems, LIST_OF_CONFIG_ITEMS_TYPE_REF);
+            }
+
+            configDocItems.addAll(superTypeConfigItems);
+
+        }
+
         for (Element enclosedElement : element.getEnclosedElements()) {
             if (!enclosedElement.getKind().isField()) {
                 continue;
diff --git a/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDocItemScanner.java b/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDocItemScanner.java
index 1e1a43e1302..f0cf97b161b 100644
--- a/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDocItemScanner.java
+++ b/core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDocItemScanner.java
@@ -5,7 +5,6 @@
 import static io.quarkus.annotation.processor.generate_doc.DocGeneratorUtil.deriveConfigRootName;
 
 import java.io.IOException;
-import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -32,15 +31,17 @@ final public class ConfigDocItemScanner {
     private final Map<String, TypeElement> configGroupsToTypeElement = new HashMap<>();
 
     private final FsMap allExtensionGeneratedDocs;
-    private final Path allConfigurationGroupsDir = Constants.GENERATED_DOCS_PATH
-            .resolve("all-configuration-groups-generated-doc");
+    private final FsMap allConfigGroupGeneratedDocs;
     private final FsMultiMap configurationRootsParExtensionFileName;
 
     public ConfigDocItemScanner() {
         this.allExtensionGeneratedDocs = new FsMap(Constants.GENERATED_DOCS_PATH
                 .resolve("all-configuration-roots-generated-doc"));
+        this.allConfigGroupGeneratedDocs = new FsMap(Constants.GENERATED_DOCS_PATH
+                .resolve("all-configuration-groups-generated-doc"));
         this.configurationRootsParExtensionFileName = new FsMultiMap(Constants.GENERATED_DOCS_PATH
                 .resolve("extensions-configuration-roots-list"));
+
     }
 
     /**
@@ -108,7 +109,7 @@ public Set<ConfigDocGeneratedOutput> scanExtensionsConfigurationItems(Properties
 
         Set<ConfigDocGeneratedOutput> configDocGeneratedOutputs = new HashSet<>();
         final ConfigDoItemFinder configDoItemFinder = new ConfigDoItemFinder(configRoots, configGroupsToTypeElement,
-                javaDocProperties, allConfigurationGroupsDir);
+                javaDocProperties, allConfigGroupGeneratedDocs, allExtensionGeneratedDocs);
         final ScannedConfigDocsItemHolder inMemoryScannedItemsHolder = configDoItemFinder.findInMemoryConfigurationItems();
 
         if (!inMemoryScannedItemsHolder.isEmpty()) {
diff --git a/extensions/oidc-common/runtime/src/main/java/io/quarkus/oidc/common/runtime/OidcCommonConfig.java b/extensions/oidc-common/runtime/src/main/java/io/quarkus/oidc/common/runtime/OidcCommonConfig.java
index 699b44a587c..60d53bb4af2 100644
--- a/extensions/oidc-common/runtime/src/main/java/io/quarkus/oidc/common/runtime/OidcCommonConfig.java
+++ b/extensions/oidc-common/runtime/src/main/java/io/quarkus/oidc/common/runtime/OidcCommonConfig.java
@@ -6,12 +6,13 @@
 import io.quarkus.runtime.annotations.ConfigGroup;
 import io.quarkus.runtime.annotations.ConfigItem;
 
+@ConfigGroup
 public class OidcCommonConfig {
     /**
-     * The base URL of the OpenID Connect (OIDC) server, for example, 'https://host:port/auth'.
+     * The base URL of the OpenID Connect (OIDC) server, for example, `https://host:port/auth`.
      * OIDC discovery endpoint will be called by default by appending a '.well-known/openid-configuration' path to this URL.
      * Note if you work with Keycloak OIDC server, make sure the base URL is in the following format:
-     * 'https://host:port/auth/realms/{realm}' where '{realm}' has to be replaced by the name of the Keycloak realm.
+     * `https://host:port/auth/realms/{realm}` where `{realm}` has to be replaced by the name of the Keycloak realm.
      */
     @ConfigItem
     public Optional<String> authServerUrl = Optional.empty();
@@ -39,9 +40,9 @@ public class OidcCommonConfig {
     /**
      * The maximum amount of time connecting to the currently unavailable OIDC server will be attempted for.
      * The number of times the connection request will be repeated is calculated by dividing the value of this property by 2.
-     * For example, setting it to '20S' will allow for requesting the connection up to 10 times with a 2 seconds delay between
+     * For example, setting it to `20S` will allow for requesting the connection up to 10 times with a 2 seconds delay between
      * the retries.
-     * Note the 'connection-timeout' property does not affect this amount of time.
+     * Note the `connection-timeout` property does not affect this amount of time.
      */
     @ConfigItem
     public Optional<Duration> connectionDelay = Optional.empty();
@@ -74,16 +75,16 @@ public class OidcCommonConfig {
     public static class Credentials {
 
         /**
-         * Client secret which is used for a 'client_secret_basic' authentication method.
+         * Client secret which is used for a `client_secret_basic` authentication method.
          * Note that a 'client-secret.value' can be used instead but both properties are mutually exclusive.
          */
         @ConfigItem
         public Optional<String> secret = Optional.empty();
 
         /**
-         * Client secret which can be used for the 'client_secret_basic' (default) and 'client_secret_post'
+         * Client secret which can be used for the `client_secret_basic` (default) and `client_secret_post`
          * and 'client_secret_jwt' authentication methods.
-         * Note that a 'secret.value' property can be used instead to support the 'client_secret_basic' method
+         * Note that a `secret.value` property can be used instead to support the `client_secret_basic` method
          * but both properties are mutually exclusive.
          */
         @ConfigItem
['extensions/oidc-common/runtime/src/main/java/io/quarkus/oidc/common/runtime/OidcCommonConfig.java', 'core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDocItemScanner.java', 'core/processor/src/main/java/io/quarkus/annotation/processor/generate_doc/ConfigDoItemFinder.java']