Mark issues fixed in a branch

You can close/fix issues by mentioning them in the commit message. If this is on a separate branch, the issue will receive a "mentioned in commit" note but not be closed until that branch is merged into master.

I'd like to see a note on the issue page that says "fixed in branch ..." so that I know that this has actually been done already but just not merged yet.

It would also be helpful for branch workers to filter these done issues away so that they can see which issues they still have to do, all before merging the branch.

(PS: Please somebody assign the "feature proposal" label as documented, I can't do that in this form.)