feat(docs, blog): add support for tags.yml, predefined list of tags

[OzakIOne]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

User request to have a predefined list of tags in a file which you can only choose from

• add unit test
  • check if everything is tested correctly
• do the same for blog plugin
• add documentation
• cleanup todos

Behavior :
undefined: search tags.yml by convention. Feature disabled if file does not exist
null/false (default): feature disabled even if tags.yml exists
tagFile.yml: search for tagFile.yml and throw if file does not exist

We check for duplicated tags permalink route and throw in case of duplication

onInlineTags	tags	behavior
ignore	false | null | undefined	do nothing
ignore	string	validate file but ignore check
ignore	undefined but file exists	validate file but ignore check
log	false | null | undefined	do nothing
log	string	process data and log
log	undefined but file exists	process data and log
warning	false | null | undefined	do nothing
warning	string	process data and warn
warning	undefined but file exists	process data and warn (default options)
throw	false | null | undefined	do nothing
throw	string	process data and throw
throw	undefined but file exists	process data and throw

Test Plan

yarn jest -t
ensureUniquePermalinks
normalizeTags
normalize tags
normalizeFrontMatterTags
processFileTagsPath
Dogfood

Test links

Guides:

• https://deploy-preview-10137--docusaurus-2.netlify.app/docs/create-doc/#doc-tags
• https://deploy-preview-10137--docusaurus-2.netlify.app/docs/blog/#blog-post-tags

API refs:

• https://deploy-preview-10137--docusaurus-2.netlify.app/docs/api/plugins/@docusaurus/plugin-content-blog/#tags
• https://deploy-preview-10137--docusaurus-2.netlify.app/docs/api/plugins/@docusaurus/plugin-content-docs/#tags

Tags pages blog:

• https://deploy-preview-10137--docusaurus-2.netlify.app/blog/tags/release/
• https://deploy-preview-10137--docusaurus-2.netlify.app/blog/tags/

Tags pages docs:

• https://deploy-preview-10137--docusaurus-2.netlify.app/tests/docs/tags/a/
• https://deploy-preview-10137--docusaurus-2.netlify.app/tests/docs/tags/

Related issues/PRs

fix #5913
#5975

[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 56	🟢 98	🟢 96	🟢 100	🟠 88	Report
/docs/installation	🟠 66	🟢 96	🟢 100	🟢 100	🟠 88	Report
/docs/category/getting-started	🟠 75	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog	🟠 68	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog/preparing-your-site-for-docusaurus-v3	🟠 63	🟢 96	🟢 100	🟢 100	🟠 88	Report
/blog/tags/release	🟠 68	🟢 100	🟢 100	🟠 80	🟠 88	Report
/blog/tags	🟠 76	🟢 100	🟢 100	🟢 90	🟠 88	Report

[netlify]

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[slorber]

We need :

  export type VersionMetadata = ContentPaths & {
    tagsFile: TagsFile | null;

    tagsPath: string;
  }

---

We probably need to modify/rename this method

type TagsFile = Record<string, Tag>

export function normalizeFrontMatterTags(
  /** Base path to append the tag permalinks to. */
  tagsPath: string,
  /** Can be `undefined`, so that we can directly pipe in `frontMatter.tags`. */
  frontMatterTags: FrontMatterTag[] | undefined = [],
  tagsFile: TagsFile
): Tag[]

[github-actions]

Size Change: +614 B (+0.04%)

Total Size: 1.72 MB

Filename	Size	Change
website/.docusaurus/docusaurus.config.mjs	27.1 kB	+155 B (+0.58%)
website/.docusaurus/registry.js	276 kB	+108 B (+0.04%)
website/.docusaurus/routes.js	180 kB	+72 B (+0.04%)
website/.docusaurus/routesChunkNames.json	120 kB	+36 B (+0.03%)
website/build/assets/js/main.********.js	855 kB	+243 B (+0.03%)

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/codeTranslations.json	2 B
website/.docusaurus/globalData.json	107 kB
website/.docusaurus/i18n.json	930 B
website/.docusaurus/site-metadata.json	2.17 kB
website/build/assets/css/styles.********.css	112 kB
website/build/index.html	38.1 kB

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