Get notifications when features get through FCP / hit beta / hit stable

[kamalmarhubi]

It's hard to keep track of all the amazing things coming up in Rust. Frequently I'll find out something I was interested in got stabilized 2-3 releases ago and I could have already been using it. Or that something I thought would have hit stable actually had some late concerns come up in FCP.

This bot may or may not fall under this project, but the data likely does.

Concrete use case

I want to use fallible conversions in a library once they become stable. I'd like to file an issue against my repo, and have rfcbot or some other friendly bot ping it once they get through FCP, or when they hit beta or stable.

Concerns

Abuse

there needs to be some protection against spamming users, and against spamming the bot that does notifications. This is especially important if it shares any infrastructure with rfcbot and any other Important Functions.

UX

I have no idea how this should work, just that I want it to.

[anp]

Since I haven't commented in a while, just wanted to say this could be really good. Related: it would be really nice to include information about tracking issues in rfcbot's database so that we can send out notices and/or display a page of things which are being considered for stabilization and in which issues, etc. I'm specifically thinking of recent post-facto disagreements with stabilizing universal impl trait -- it could be really nice to let people know that an FCP has been started for stabilizing a specific RFC, even if the tracking issue is ostensibly tracking multiple.

In particular, I'm thinking that maybe doing more communication about stabilizations that touch multiple RFCs might ward off disagreements that arise out of people not knowing what's being stabilized and when.

cc @aturon