Most of CodeMirror doesn't allow tabs or trailing whitespace. This removes some from a few mode files. Our repository has commit hooks checking for tabs, which was warning us about these tabs.
You don't accept whitespace only changes like this (because it does much with the history) we can workaround this on our end.
Remove tabs and trailing whitespace in a few modes
Merged. And I've set up the linter to complain about tabs and trailing whitespace, in an attempt to keep the code free of them in the future.