Store potential pull request numbers on issue

[lunny]

Once a pull request claim it will fix some issues, then these issues could save them and display them on issues list and issue view page.

[guillep2k]

It's only a display thing, as the information is already there. To get the info, we just need to get the issues' comments whose RefAction is XRefActionCloses (or XRefActionReopen, eventually). We need to be careful as there might be more than one PR claiming to close an issue, but other than that the info is there.

[InExtremaRes]

Is this proposal somewhat similar to this GitHub feature (with maybe different UI, of course)?

That would be great!

[lunny]

@guillep2k We could chose the first open pull request as a beginning. Show more than 1 pull links on pull request list page is more complicated on UI.

[lunny]

This should be resolved by #31899