Close all requests for additional targets

[Mark-Simulacrum]

I would like to suggest we close out rust-lang/rust issues asking for targets to be moved between tiers or added, at least when those look to be stale. The right way I believe for people to propose targets for tier movement is with a t-compiler mcp these days (per target tier policy). In other words, something explicitly ephemeral.

[Mark-Simulacrum]

Cc rust-lang/rust#42639 (comment)

[Mark-Simulacrum]

Drafting some language to post on such issues:

Hey all -- the infrastructure team has discussed the best way for folks to check if CI capacity is available for moving targets up to further tiers, and we recommend that those requesting a target be promoted to any tier above tier 3 (i.e., those targets requiring CI time) ask on Zulip in #t-infra whether there's spare CI time for a given target.

In the meantime, we're going to close any issues requesting a particular target be added in favor of following the target tier policy process, which documents the expected actions to take for each level of promotion for some target. Feel free to ask on Zulip in #t-compiler if there's any questions about that.

This would get posted on any target request issue, essentially. I don't think it's helpful to have these issues open for a long time, and though it's probably not actively harmful, keeping the issue tracker a little tidier always seems positive to me.

[Mark-Simulacrum]

Discussed in infra meeting today and agreed we could go ahead with something like this.