* gtk/tmpl/gtkbbox.sgml: Remove references to nonexisting functions.

        * gtk/tmpl/gtkcolorseldlg.sgml, gtk/tmpl/gtkdrawingarea.sgml,
        gtk/tmpl/gtkmain.sgml, gtk/tmpl/gtkhseparator.sgml,
        gtk/tmpl/gtktree.sgml, gtk/tmpl/gtkradiobutton.sgml,
        gtk/tmpl/gtkradiomenuitem.sgml:
        Replace references to deprecated functions.

        * gtk/tmpl/gtkhbbox.sgml,gtk/tmpl/gtkvbbox.sgml: Minor fixes.