run-tests: fix broken regular expression
The regular expression in use passed tests because the test repo only
has single-digit changesets present. When I tried to use this for real
today, it broke, because the regular expression would only match a
single digit.
https://xkcd.com/1171/, or something like that.
#require test-repo
$ 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