encoding: use raw strings for encoding arguments This prevents the internals of Python from coercing a unicode to str on Python 2 and makes tests run with HGUNICODEPEDANTRY=1 a lot happier. Differential Revision: https://phab.mercurial-scm.org/D6051

revsetlang: use sysbytes() instead of blind encode() Otherwise we will call str.encode() on Python 2, which is wrong. sysbytes() does encode('utf-8') on Python 3. But the source is guaranteed ASCII, so it shouldn't matter. With this change, `hg` now runs with `HGUNICODEPEDANTRY=1` set. However, several tests are failing. Differential Revision: https://phab.mercurial-scm.org/D6050