Paul Eggert wrote:
> A proposed patch is attached; it worked for me.

On further thought, the code affects global settings so it should be done only 
if FRAME is nil.  Also, it should treat double-quotes like single-quotes, and 
the ASCII approximations should use straight quotes.  This code is separable 
from Bug#20545, and is also separable from the issue of how to quote in doc 
strings, as the code is useful whenever text with English quotes appears on an 
obsolescent display lacking them.  So I installed the attached patch.