CLN: remove merge-pr script, clean Exception in tm, doc
I count 131 of these ATM, some of which we'll end up marking as intentionally non-specific.
I never use it anymore, and I think we fully switched to using github's button to merge PRs. But maybe some people still use it to fetch PR's branchs and push back there? yeah i think we can blow away the merge script Updated to remove merge-pr.py Thanks!