[Doc-SIG] reserved characters

[Edward D. Loper]

I'm thinking of adding a number of "reserved characters" to STminus,
that specific versions of ST may decide to use or not use.  They
would redefine their own ReservedCharacter production accordingly..
So:
  1. Is this a Good Idea?
  2. What characters should be included?  Clearly at least '#' for
     STpy.  Other possibilities are backquote, at sign, exclamation
     mark, etc.  I'd like to reserve as few as we can get away with,
     since the more characters are reserved, the less useful a 
     program written to work on *any* StructuredText document can
     be.

-Edward