bug#2946: 23.0.92; output of describe-font-internal and doc string of font-info

> Doc string of font-info no longer describes the third element it
> returns, CHARSET.  It used to be described as "CHARSET is the charset
> displayed by the font".
>  
> describe-font-internal no longer displays the CHARSET information for
> a font. It used to be described: e.g., "ascii (ASCII (ISO646 IRV))".

Also, it seems that what is called "size" in the doc of both `font-info' and
`describe-font' would be better called "width".

From `font-info':
 "SIZE is the maximum bound width of the font"
                            ^^^^^

`describe-font', in particular, should use "width":

       full name:
-outline-Lucida Console-normal-r-normal-normal-14-105-96-96-c-*-iso8859-1
            size:  8
          height: 14
 baseline-offset:  0
relative-compose:  0

Also, why isn't command `describe-font' mentioned in the Emacs manual? That
would be a good place to mention it and explain what each of its components
means.