Virtual function declarations should specify only one of `virtual`, `final`, or `override`, as per the Mozilla C++ style guide:
https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Coding_Style
This lint warns about:
virtual void Bad1() final
void Bad2() final override
void Bad3() override final
Caveats: This lint doesn't warn about `virtual void NotBad() override` at this time because there are 8000+ instances. It also doesn't warn about function declarations that span multiple lines because the regex can't match across line breaks.
MozReview-Commit-ID: LcBsOAKKgz7
--HG--
extra : rebase_source : 4da72ffac59acdc9796e3f540f24bb97af989cd0
c6373306f8