todo_comment_linter(except_regex=) fails with capture groups

[MichaelChirico]

lint("# abc\n", todo_comment_linter('abc', except_regex = "(abc)"))
# Error in `h()`:
# ! Linter `linter()` failed in /tmp/Rtmp6XgIZm/file2adee8120fb1df:
# invalid argument type
# Run `rlang::last_trace()` to see where the error occurred.

The error is really confusing too. It's easy to forget to use ?: when writing a regex (and it's not clear that's a good requirement). Primarily this is due to rex::re_matches() changing output type.

[MichaelChirico]

Filed r-lib/rex#94 as an upstream FR.