bug#5327: 23.1; unload-feature-special-hooks add fill-nobreak-predicate

[Kevin Ryde <user42@zip.com.au>]

While nosing around the unload-feature stuff I wondered if
unload-feature-special-hooks should include fill-nobreak-predicate, as
it's a hook now.

The damage from leaving an unloaded func there is limited to paragraph
filling, and is likely to be either buffer local, or be autoloaded and
then end up ok anyway.  You can see a bad effect currently for instance
with

    M-x sgml-mode
    M-x unload-feature sgml-mode
    type in a long line to be filled
    M-q
    => Symbol's function definition is void: sgml-fill-nobreak


In GNU Emacs 23.1.1 (i486-pc-linux-gnu, GTK+ Version 2.16.5)
 of 2009-09-14 on raven, modified by Debian
configured using `configure  '--build=i486-linux-gnu' '--host=i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.1/leim' '--with-x=yes' '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars' 'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -g -O2' 'LDFLAGS=-g' 'CPPFLAGS=''