tests/test-gendoc-zh_TW.t

windows: don't consider '$$' to be an escaped '$' when translating to cmd.exe

This functionality was inherited from `os.path.expandvars()`.  But the point of
adding this translating code is to be able to write a portable hook, and bash
wouldn't replace '$$' with '$'.  Escaping with '\' works, and is portable.

#require docutils gettext

  $ $TESTDIR/check-gendoc zh_TW
  checking for parse errors