[3.12] gh-101137: Add text/x-rst to mimetypes (GH-118593)

[sobolevn]

(cherry picked from commit 1511bc9)

• Issue: Add .rst to mimetypes #101137

[jaraco]

Let's hold off on merging this until there's a decision on #118594 (and only include this backport if markdown is backported and there's no objection to merging this one).

[bedevere-app]

When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.

[hugovk]

Let's hold off on merging this until there's a decision on #118594 (and only include this backport if markdown is backported and there's no objection to merging this one).

That was merged, albeit with a post-merge objection: #118594 (comment)

Maybe close this backport?

[jaraco]

Let's hold off on merging this until there's a decision on #118594 (and only include this backport if markdown is backported and there's no objection to merging this one).

That was merged, albeit with a post-merge objection: #118594 (comment)

Maybe close this backport?

I wouldn't characterize that as a post-merge objection, more an objection about the process than the change itself. Since the markdown change was backported and not reverted, it seems prudent to also backport the rst change, as those two changes were symmetrical. I advocate to merge this change.