private static @NotNull Stream<String> getAssociatedExtensions(@NotNull LanguageFileType fileType) {
    return FileTypeManager.getInstance().getAssociations(fileType)
      .stream()
      .filter(ExtensionFileNameMatcher.class::isInstance)
      .map(ExtensionFileNameMatcher.class::cast)
      .map(ExtensionFileNameMatcher::getExtension);
  }
private static @NotNull Stream<String> getAssociatedExtensions(@NotNull LanguageFileType fileType)