Bug 1799982 - Remove uses of inline flags from XPIDL regexps. r=xpcom-reviewers,kmag

Bug 1799982 - Remove uses of inline flags from XPIDL regexps. r=xpcom-reviewers,kmag

Apparently the use of these is being turned into an error in Python 3.11.
Fortunately, our uses appears to be rather trivial.

For t_multilinecomment and t_LCDATA, I dropped the (?s) flag and just
replaced the one use of . with (\n|.). (?s) means DOTALL, which means
that dot includes any character, including a newline. Otherwise it means
dot includes any character except a newline.

I took the new t_singlelinecomment from IPDL's parser.py, so I assume
it is reasonable enough. t_multilinecomment is also now the same as
in IPDL.

Differential Revision: https://phabricator.services.mozilla.com/D161738

Gbp-Pq: Topic fixes
Gbp-Pq: Name Bug-1799982-Remove-uses-of-inline-flags-from-XPIDL-r.patch