[include-cleaner] Record whether includes are spelled with <angle> quotes

[include-cleaner] Record whether includes are spelled with <angle> quotes

This is needed to accurately remove headers with tooling::IncludeHeaders in the
rare cases where <foo> and "foo" resolve to something different.

This is also nice to have in HTML report and command-line -print=changes output.

Differential Revision: https://reviews.llvm.org/D139018