Triager log/How to become a triager

Currently we have:

• a developer log
• an how to become a core developer pages

As far as I know, there is no equivalent to the developer log for triagers, and there is a section about becoming triagers.

I think we should:

• Add a triager log (possibly generated by the file proposed in #848)
• Add a link to the "becoming a core dev" page to the "becoming triager" section, or move both to the same page
• Improve the documentation on how to become a triager, including steps such as
  • making an official announcement on Discourse
  • adding the new triager to the triagers team on GitHub
  • reclaiming the GitHub mannequin
  • join the Discord server
• Add links between the developer/triager logs and the "becoming *" section and the other way around

まず、issue にリンクされている developer log、core developer、triaging の各ページを読んでから、#848 で提案されているファイルを確認してください。triager log が存在し、becoming-triager guidance が一覧にあるオンボーディング手順を網羅し、関連するページ同士が相互にリンクされていれば完了です。