Remove GA features from experimental doc (#9622)
Remove GA features from experimental doc (#9622)

* Remove GA features from experimental doc

* Update experimental-features.md

* Update experimental-features.md

* Update wording

Co-authored-by: Lilian Lee <c684465c17314189c18707959627e2ec4fdec2d0@pingcap.com>
pingcap/docs,pingcap/docs,pingcap/docs