Change show_help signal to return gboolean instead of void. This allows

Change show_help signal to return gboolean instead of void. This allows

* gtk/gtkwidget.[ch]:
Change show_help signal to return gboolean instead of void. This
allows the keypress which invokes the signal to be propagated to the
focus widgets ancestors if not handled by the focus widget.

* gtk/gtktoolips.[ch]
Change _gtk_tooltips_show_tip () to return a gboolean indicating
whether widget has tooltip to display.