Update C++ standard for clang-format to 11, apply updated formatting rules

[ManifoldFR]

• pre-commit config : actually delegate to .clang-format config file
• .clang-format : increase Standard to Cpp11
• pre-commit: run all
• .git-blame-ignore-revs : update
• Update CHANGELOG

This PR would require setting the minimum required version of the C++ standard to 11 I think, because stuff like vector<A<T>> without a space between the last two angle brackets for templates doesn't work on some C++03 compilers if I recall correctly.

[ManifoldFR]

I think we should merge this before #545. Then I can pop off the last commit off of that PR since we won't have to fight the formatting.