Add buttons to `clear-pr-merge-commit-message` and related features

Description

Instead of automatically clearing the field, I wonder if we could add some buttons in the mergeability box to:

• sync-pr-commit-title
• clear-pr-merge-commit-message
• https://github.com/refined-github/refined-github/issues/2103
• https://github.com/refined-github/refined-github/issues/1264

This issue replaces:

• https://github.com/refined-github/refined-github/issues/4606

Avoiding automatic replacement would also avoid:

• https://github.com/refined-github/refined-github/issues/4101 (the issue would still exist since it’s GitHub’s, probably, but since we won’t automatically change the fields, it won’t happen “because of RGH”)

Related:

• https://github.com/refined-github/refined-github/issues/3964
• https://github.com/refined-github/refined-github/issues/4531

Screenshot

Example URL

https://github.com/refined-github/refined-github/pull/3

[JelteF]

We need to decide what to do with our current features regarding PR titles, if we can detect a custom setting and avoid overriding it.

Since one of the settings that github provides is exactly what is being done by refined github now, I don’t think there’s a reason to keep these settings. In the current state it gives you less configurability than Github does. I think the clear-pr-commit-title setting should at least be disabled by default, because it now messes up the repo settings.

[fregante]

GitHub added some controls over this, which are likely to stay “per-repo”:

https://github.blog/changelog/2022-08-23-new-options-for-controlling-the-default-commit-message-when-merging-a-pull-request/

We need to decide what to do with our current features regarding PR titles, if we can detect a custom setting and avoid overriding it.

Edit: we can’t detect it, but we added a notice so the user knows what’s happening and can disable the feature.