accept <case> and [cond] in ChangeLog

accept <case> and [cond] in ChangeLog

Only '(' and ':' currently terminate file lists in ChangeLog entries
in the ChangeLog parser.  This rules out such legitimate entries as:

* filename <CASE>:
* filename [COND]:

This patch extends the ChangeLog parser to recognize these forms.

for  contrib/ChangeLog

	* gcc-changelog/git_commit.py: Support CASE and COND.
	* gcc-changelog/test_patches.txt: Add test.
	* gcc-changelog/test_email.py: Add test.

Co-Authored-By: Martin Liska <mliska@suse.cz>
(cherry picked from commit a759bfc7cf238b9fc5bf97884297fc69d8cdf2b5)