Enable [range-diff], [transfer] and [view-all-comments-link] org-wide

[Urgau]

Following #2294, let's enable three more handlers org-wide:

• [range-diff]: adds a link to show a range-diff when a PR is rebased onto a different base commit
• [transfer]: enables issue transfers within the org
• [view-all-comments-link]: adds a "View all comments" link on the issue/PR body that shows all the comments of it

cc @Mark-Simulacrum @jieyouxu

[Kobzol]

View all comments and transfer seems harmless enough. Range diff might be a bit too chatty on some repos, but we'll see what happens.

View changes since this review

[Urgau]

I'm thinking about this for the announcement:

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Next up, we’re turning on three more triagebot features across all triagebot-enabled rust-lang repositories:

• [range-diff] – adds a link to show what changed when a PR gets rebased
• [transfer] – enables @rustbot transfer to move issues between repos in the org
• [view-all-comments-link] – adds a "View all comments" link to see the full GitHub conversation in one place

As before, any repository can opt out if needed.

[Mark-Simulacrum]

[view-all-comments-link] – adds a "View all comments" link to see the full GitHub conversation in one place

Does this end up in PR merges for GitHub-owned merges (e.g., merge queues)? Can we avoid that? cc #2302

Maybe not a hard blocker but could be worth waiting a little more there. Maybe we can recommend folks setup a bookmarklet that redirects for that instead?