rust-filepatterns: fix type of warnings tuple to (bytes, bytes)
Otherwise warn() in match.py would fail if the warning contains non-ASCII
character.
We might want to add a thin ByteString wrapper around Vec<u8> to
implement ToPyObject<ObjectType = PyBytes>, but I'm not sure.
#require docutils gettext
Error: the current ro localization has some rst defects exposed by
moving pager to core. These two warnings about references are expected
until the localization is corrected.
$ $TESTDIR/check-gendoc ro
checking for parse errors
gendoc.txt:58: (WARNING/2) Inline interpreted text or phrase reference start-string without end-string.
gendoc.txt:58: (WARNING/2) Inline interpreted text or phrase reference start-string without end-string.