bug#21447: 25.0.50; doc string of `character-fold-search'

[Drew Adams]

1. This should be a defcustom, not a defvar.  But this improvement has
apparently already been agreed to (per emacs-devel correspondence).

2. The doc string should treat characters as characters.  It should not
just put " and a inline, with no syntax making them stand out.

They should be written as `?\"' and `?a'.  Or at least as ?\" and ?a.
Or possibly as `"' and `a'.

3. Please replace "(and then some)" by some indication of what is meant
by it.  Just say that `?a' also matches other kinds of "a-like"
characters, such as <GIVE AN EXAMPLE>.


In GNU Emacs 25.0.50.1 (i686-pc-mingw32)
 of 2015-08-16 on LEG570
Bzr revision: f7ee23e587b01f179284b5554c67d579a2def676
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --host=i686-pc-mingw32 --enable-checking=yes,glyphs'