Create Pull Request templates for common actions

[pitaj]

Opening this issue so we can get central feedback from various teams on what categories of PRs we should support.

My initial list:

• New unstable library API
• Feature stabilization
• Updating subtree/submodule
• Experimental PR (S-experimental, r? ghost, opens as draft)

[jyn514]

What does "infrastructure" mean here? the changes for infra are pretty broad, i can't think of any info that would be useful across all of them. ditto for rustdoc.

[pitaj]

Totally fair. Those are broad, and would essentially just be there to add the T- label. If you have more specific categories in mind, feel free to share.

[jyn514]

We have autolabels already, i don't we should add templates just for labels. If we're going to do this, it should be so the PR author can more quickly get feedback without having to wait for a reviewer to point them to the right process, things like that - it's an aid for review basically.

[nakul1710]

@pitaj @jyn514 it is you good issue for new comer . I want to contribute in it can you assign it to me

[pitaj]

@nakul1710 sorry we haven't really decided what templates we want yet. I've removed the easy label.

Once this issue is more fleshed out I'll add that label back. Thanks

[vincenzopalazzo]

I think the Feature stabilization issue (in order to request one feature stabilization) could be a good one; currently, there is no way to do it. You need just to ping people around

[programmerjake]

one thing that could benefit from a template though isn't necessarily all that common is updating a subtree/submodule