check-config: look for ui.configwith
We previously weren't looking for this config helper. And, surprise,
profiling.py references config options without docs.
If I tried hard enough, I could have combined the regexps using a
positive lookbehind assertion or something. But I didn't want to make
my brain explode.
At some point, we should probably do this linting at the tokenizer or
ast layer. I'm not willing to open that can of worms right now.
Our full contribution guidelines are in our wiki, please see:
https://www.mercurial-scm.org/wiki/ContributingChanges
If you just want a checklist to follow, you can go straight to
https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist
If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).