bug#3526: 23.0.94; `list-character-sets' display

[Drew Adams]

Your changes look good to me, Jason. 

> > Some of the charsets listed as supplementary are obsolete; 
> > they were used in Emacs versions prior to version 23.
> >
> > [Is that correct? If so, why not get rid of these here? Why 
> > show stuff that is no longer in Emacs?]
>  
> I think charsets like mule-unicode-0100-23ff, which existed 
> in previous versions because of technical restrictions on the
> size of charsets, may be referred to by old lisp code, so we
> need to keep them around for compatibility.

That we need, for backward compatibility, to keep around code that is not used
by the current version is one thing. That doesn't mean, however, that we should
show those charsets to the Emacs 23 user in a help display.

I can't judge whether that display could be useful to Emacs 23 users or not -
it's your call. Typically, only the current release is described in user doc
(and in the UI). Compatibility issues are sometimes called out in the doc, but
more often that is done in release notes (e.g. NEWS).

> >>   To find out which charset a character in the buffer belongs to,
> >
> > To find out which charset a character belongs to,
>   
> Since the described function acts on a character in a buffer, I think 
> the original wording is correct.

"the buffer" confuses more than it helps here, IMO. It could easily be taken to
refer to the list-charsets display buffer, given the context so far. And "put
point before it and type @kbd{C-u C-x =}" can only apply to a character in a
(displayed) buffer anyway, so "in the buffer" is redundant at best and confusing
at worst.

But if this sentence is moved, as I suggested, so that the context is no longer
the list charsets display, then that possible confusion can be removed.
Personally, I would say just this:

"To show the charset of the character at point, use @kbd{C-u C-x =}."

There is no need to describe, in addition, how to make a given character become
the character at point.