Create relnotes-interest-group ping group

[jieyouxu]

Tracking issue: rust-lang/rust#133334

This ping group is intended for contributors who would like to get pinged on release notes PRs (PR modifying RELEASES.md and the release blog post), intended to help double-check release notes. As @BoxyUwU said:

If we're going to do this I'd probably prefer having new ping group or something rather than pinging lang directly. This isn't really lang teams area so it's mostly just a "here are some people interested in knowing the release is happening" ping at which point why not do something that other people can use if they want to take an early look at the release posts

For more context, see https://rust-lang.zulipchat.com/#narrow/channel/241545-t-release/topic/Please.20CC.20lang.

I don't know if this needs sign-off from anyone... Maybe T-release lead... so I guess

r? @Mark-Simulacrum

[traviscross]

I'll note that @ehuss suggested to me an interesting alternative approach to this, which is to configure triagebot to emit pings when the RELEASES.md file changes and when a -Rust-1\.\d+\.\d+\.md blog post is created.

(Supporting the latter would require some work on triagebot.)

[jieyouxu]

I'll note that @ehuss suggested to me an interesting alternative approach to this, which is to configure triagebot to emit pings when the RELEASES.md file changes and when a -Rust-1\.\d+\.\d+\.md blog post is created.

I think that's another valid approach. I will note that using the triagebot notifications on file changes might not be ideal here because that would trigger even on PRs that just do typo fixes (based on existing file-based notifs on r-l/r usages). Whereas a separate notification group is much more deliberate for both T-release as well as people interested in being pinged for the main relnotes PRs (not for typo fixes) I would think.

[Noratrieb]

This looks ready, @Mark-Simulacrum