dirstate-v2: Use "byte sequence" in docs The patch originally sent as https://phab.mercurial-scm.org/D11546 used "byte string" but that was changed during review to avoid suggesting Unicode or character encodings. However "byte range" sounds to be like a range of *indices* within a byte string/sequence elsewhere. This changes to "byte sequence". Python docs use "sequence" a lot when discussing the `bytes` type: https://docs.python.org/3/library/stdtypes.html Differential Revision: https://phab.mercurial-scm.org/D11623