templatefilters: fix crash by string formatting of '{x|splitlines}'
Before, it crashed because mapping['templ'] was missing. As it didn't support
the legacy list template from the beginning, we can simply use hybridlist().
#require test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "$TESTDIR"/..
New errors are not allowed. Warnings are strongly discouraged.
$ hg files "set:(**.py or **.txt) - tests/**" | sed 's|\\|/|g' |
> python contrib/check-config.py