Add a way to view and apply MR review suggestions

Problem to solve

With Added suggestions to public notes API (gitlab!192209 - merged) in the works, glab should soon have access to that special note type. Currently, glab mr view --comments does not render a suggestion in any patch-relevant manner, see example below.

Proposal

Add something that helps to review suggestions and apply or reject them, individually or in bulk, like the UI offers. This could be an interactive mode, showing the suggestion(s) in a patch-formatted manner, with a/y & r/n shortcurts or similar.

Ideally, the resulting commit(s) is performed locally, so that further edits like adding co-authors can be performed before git pushing a new MR version.

Further details

• example

$ glab mr view --comments | grep -A5 'ashrafkhamis commented'
ashrafkhamis commented 2025-05-27 08:52:47.626 +0000 UTC
```suggestion:-1+0
When you plan your maintenance window, you should include the `ANALYZE` duration
because GitLab performance might be significantly degraded during this operation.
```

ashrafkhamis commented 2025-05-27 08:59:43.503 +0000 UTC
@katrinleinweber-gtlb Thanks, I've applied a couple of small tweaks. Approving and merging :rocket:

Links / references