crecord: convert an instance of bytes to str
Caught by pytype:
File "/mnt/c/Users/Matt/hg/mercurial/crecord.py", line 1154, in printstring: Function _CursesWindow.addstr was called with the wrong arguments [wrong-arg-types]
Expected: (self, str: str, ...)
Actually passed: (self, str: bytes, ...)
Differential Revision: https://phab.mercurial-scm.org/D10203