fsmonitor: normalize exception types to bytes Unavailable.msg should now always be bytes. We also rename Unavailable.__str__ to __bytes__ as it always returns bytes. We make __str__ a simple wrapper that decodes that result to str. There's probably some excessive strutil.forcebytestr() in fsmonitor/__init__.py now. But at least the exceptions around type coercion should now be gone. Differential Revision: https://phab.mercurial-scm.org/D7214