JavaDoc popup renders incorrectly
### Apache NetBeans version

Apache NetBeans 16

### What happened

The JavaDoc popup does not render the text in some tags. Specifically text in fixed-width code style appears to be missing.  For example references to system properties in the JavaDoc for ClassLoader.getSystemClassLoader().

### How to reproduce

In a Java editor type "ClassLoader." hit the autocompete shortcut and select the getSystemClassLoader() method such that the JavaDocs appear.  Notice that there are missing parts compared to viewing the same documentation in a web browser. Such as:

    If the system property "java.system.class.loader" is defined when...

appearing instead as:

    If the system property "" is defined when...

### Did this work correctly in an earlier version?

No / Don't know

### Operating System

macOS 13.2

### JDK

JDK 17.0.6

### Apache NetBeans packaging

Apache NetBeans binary zip

### Anything else

_No response_

### Are you willing to submit a pull request?

Yes

### Code of Conduct

Yes
diff --git a/java/java.sourceui/src/org/netbeans/api/java/source/ui/ElementJavadoc.java b/java/java.sourceui/src/org/netbeans/api/java/source/ui/ElementJavadoc.java
index ed8edb9fa3..6d1df08284 100644
--- a/java/java.sourceui/src/org/netbeans/api/java/source/ui/ElementJavadoc.java
+++ b/java/java.sourceui/src/org/netbeans/api/java/source/ui/ElementJavadoc.java
@@ -39,6 +39,7 @@ import com.sun.source.doctree.SinceTree;
 import com.sun.source.doctree.SnippetTree;
 import com.sun.source.doctree.StartElementTree;
 import com.sun.source.doctree.SummaryTree;
+import com.sun.source.doctree.SystemPropertyTree;
 import com.sun.source.doctree.TextTree;
 import com.sun.source.doctree.ThrowsTree;
 import com.sun.source.doctree.UnknownBlockTagTree;
@@ -1332,6 +1333,19 @@ public class ElementJavadoc {
                     List<? extends DocTree> summary = summaryTag.getSummary();
                     sb.append(inlineTags(summary, docPath, doc, trees, null));
                     break;
+                case SYSTEM_PROPERTY:
+                    SystemPropertyTree systemPropTag = (SystemPropertyTree) tag;
+                    sb.append("<code>"); //NOI18N
+                    sb.append(systemPropTag.getPropertyName());
+                    sb.append("</code>"); //NOI18N
+                    break;
+                default:
+                    sb.append("<code>"); //NOI18N
+                    try {
+                        sb.append(XMLUtil.toElementContent(tag.toString()));
+                    } catch (IOException ioe) {}
+                    sb.append("</code>"); //NOI18N
+                    break;
             }
         }
         return sb;
['java/java.sourceui/src/org/netbeans/api/java/source/ui/ElementJavadoc.java']