bug#1868: Default fontset not discussed in documentation

[Juanma Barranquero]

Package: emacs,documentation
Version: 23.0.60
Severity: minor

(emacs)Fonsets describes the "startup fontset" (fontset-startup) and
the "standard fontset" (fontset-standard), but it does not mention the
"default fontset" (fontset-default).

(elisp)Fonsets mentions the default fontset in the description of
`set-fontset-font', with:

     If NAME is `nil', this function modifies the default fontset,
     whose short name is `fontset-default'.

However, what is the default fontset, its uses, or how does it relates
to fontset-startup and fontset-standard, are never discussed anywhere.