Update frontend guideline (#19901)
Update frontend guideline (#19901)

* update frontend guideline

* "Native" => "Vanilla JS", fix typo comma.

Co-authored-by: Lunny Xiao <0b0704cdf8f0790c6f1df1f74c38be95a8917ed2@gmail.com>
go-gitea/gitea,go-gitea/gitea,go-gitea/gitea