feat: doc tags (same as blog tags) (#3646)

* [v2] tags to doc, same as tags to blog - [IN PROGRESS]

- Addition of plugin-content-docs

- Addition of DocTagsListPage in `docusaurus-theme-classic`

! Error exists for this commit towards the theme aspect and help required.

Commit towards #3434

* docs: make tags list page work

* temp: disable onBrokenLinks

* theme bootstrap: create DocTagsListPage

* DocTagsPage added and functionality too

- individual doc tag page added to show docs for that specific tag

* Added all Docs Tags Link

* add some shared tag utils

* move tag tests to _dogfooding

* fix type

* fix some tests

* fix blog test

* refactor blog post tags handling

* better yaml tag examples

* better dogfood md files

* refactor and factorize theme tag components

* finish DocTagDocListPage

* Extract DocItemFooter + add inline tag list

* minor fix

* better typings

* fix versions.test.ts tests

* add tests for doc tags

* fix tests

* test toTagDocListProp

* move shared theme code to tagUtils

* Add new theme translation keys

* move common theme code to tagUtils + add tests

* update-code-translations should handle theme-common

* update french translation

* revert add translation

* fix pluralization problem in theme.docs.tagDocListPageTitle

* add theme component configuration options

* add more tags tests

* add documentation for docs tagging

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

packages/docusaurus-plugin-content-blog/src/blogUtils.ts

@@ -16,6 +16,7 @@ import {
   BlogPost,
   BlogContentPaths,
   BlogMarkdownLoaderOptions,
+  BlogTags,
 } from './types';
 import {
   parseMarkdownFile,
@@ -26,6 +27,8 @@ import {
   posixPath,
   replaceMarkdownLinks,
   Globby,
+  normalizeFrontMatterTags,
+  groupTaggedItems,
 } from '@docusaurus/utils';
 import {LoadContext} from '@docusaurus/types';
 import {validateBlogPostFrontMatter} from './blogFrontMatter';
@@ -43,6 +46,20 @@ export function getSourceToPermalink(
   );
 }
 
+export function getBlogTags(blogPosts: BlogPost[]): BlogTags {
+  const groups = groupTaggedItems(
+    blogPosts,
+    (blogPost) => blogPost.metadata.tags,
+  );
+  return mapValues(groups, (group) => {
+    return {
+      name: group.tag.label,
+      items: group.items.map((item) => item.id),
+      permalink: group.tag.permalink,
+    };
+  });
+}
+
 const DATE_FILENAME_REGEX = /^(?<date>\d{4}[-/]\d{1,2}[-/]\d{1,2})[-/]?(?<text>.*?)(\/index)?.mdx?$/;
 
 type ParsedBlogFileName = {
@@ -240,6 +257,8 @@ async function processBlogSourceFile(
     return undefined;
   }
 
+  const tagsBasePath = normalizeUrl([baseUrl, options.routeBasePath, 'tags']); // make this configurable?
+
   return {
     id: frontMatter.slug ?? title,
     metadata: {
@@ -250,7 +269,7 @@ async function processBlogSourceFile(
       description,
       date,
       formattedDate,
-      tags: frontMatter.tags ?? [],
+      tags: normalizeFrontMatterTags(tagsBasePath, frontMatter.tags),
       readingTime: showReadingTime ? readingTime(content).minutes : undefined,
       truncated: truncateMarker?.test(content) || false,
     },