[mi, doc] mention escape sequences

[Eli Zaretskii]

> From: Vladimir Prus <vladimir@codesourcery.com>
> Date: Wed, 11 Jun 2008 18:07:25 +0400
> 
> Note that parse_escape function supports more than C language escape
> sequences, it seems, but given that the function has no comments on
> those sequences, and given that manual does not say anything about
> that either, I don't feel like reverse-engineering the code to
> document the exact rules. "As in C" as sufficient, I think, for MI
> manual.

Maybe not all exact rules, but a single example would be good, I
think.  After all ``escape sequences'' is a heavily overloaded term,
even with the "C" qualifier, and without an example, the reader might
be left in doubt.

> Escape sequences are not allowed in @var{non-blank-sequence}.

How do you mean ``not allowed''?  Perhaps you mean ``not
interpreted'', i.e. output verbatim?