Close#23241
Before: press Ctrl+Enter in the Code Review Form, a single comment will
be added.
After: press Ctrl+Enter in the Code Review Form, start the review with
pending comments.
The old name `is_review` is not clear, so the new code use
`pending_review` as the new name.
Co-authored-by: delvh <leon@kske.dev>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>