tests/test-empty-dir.t

typing: explicitly set the return type of `_InnerRevLog.raw_text()`

Somewhere between cd72a88c5599 and 2fd44b3dcc33, pytype changed the return type
from `Tuple[_T1, Any, bool]` to `Any`.  Both are wrong.  `mdiff.patches()` is an
alias for `mpatch.patches()`, which is selected via module policy (and breaks
the ability to infer the types).  However, `cext`, `cffi`, and `pure`
implementations all agree it returns bytes.

  $ hg init

  $ echo 123 > a
  $ hg add a
  $ hg commit -m "first" a

  $ mkdir sub
  $ echo 321 > sub/b
  $ hg add sub/b
  $ hg commit -m "second" sub/b

  $ cat sub/b
  321

  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ cat sub/b 2>/dev/null || echo "sub/b not present"
  sub/b not present

  $ test -d sub || echo "sub not present"
  sub not present