feat(content-docs): expose isCategoryIndex matcher to customize conventions (#6451)

Co-authored-by: sebastienlorber <lorber.sebastien@gmail.com>

website/docs/api/plugins/plugin-content-docs.md

@@ -77,6 +77,12 @@ type PrefixParser = (filename: string) => {
   numberPrefix?: number;
 };
 
+type CategoryIndexMatcher = (doc: {
+  fileName: string;
+  directories: string[];
+  extension: string;
+}) => boolean;
+
 type SidebarGenerator = (generatorArgs: {
   item: {type: 'autogenerated'; dirName: string}; // the sidebar item with type "autogenerated"
   version: {contentPath: string; versionName: string}; // the current version
@@ -88,6 +94,7 @@ type SidebarGenerator = (generatorArgs: {
     sidebarPosition?: number | undefined;
   }>; // all the docs of that version (unfiltered)
   numberPrefixParser: PrefixParser; // numberPrefixParser configured for this plugin
+  isCategoryIndex: CategoryIndexMatcher; // the default category index matcher, that you can override
   defaultSidebarItemsGenerator: SidebarGenerator; // useful to re-use/enhance default sidebar generation logic from Docusaurus
 }) => Promise<SidebarItem[]>;
 
@@ -141,6 +148,7 @@ const config = {
     item,
     version,
     docs,
+    isCategoryIndex,
   }) {
     // Use the provided data to generate a custom sidebar slice
     return [
@@ -274,15 +282,15 @@ website/i18n/[locale]/docusaurus-plugin-content-docs
 │
 │ # translations for website/docs
 ├── current
-│   ├── api
-│   │   └── config.md
-│   └── getting-started.md
+│   ├── api
+│   │   └── config.md
+│   └── getting-started.md
 ├── current.json
 │
 │ # translations for website/versioned_docs/version-1.0.0
 ├── version-1.0.0
-│   ├── api
-│   │   └── config.md
-│   └── getting-started.md
+│   ├── api
+│   │   └── config.md
+│   └── getting-started.md
 └── version-1.0.0.json
 ```