Comment parsing: parse "<blah" as an HTML tag only if "blah" is a known tag
name.  This should reduce the amount of warning false positives about bad HTML
in comments when the comment author intended to put a reference to a template.
This change will also enable us parse the comment as intended in these cases.

Fixes part 1 of PR13374.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162407 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed