IBusFactory: Fix syntax of gtk-doc comment
IBusFactory: Fix syntax of gtk-doc comment

This was always invalid, but older versions of gobject-introspection
accepted it.

BUG=https://bugzilla.gnome.org/show_bug.cgi?id=689354

Review URL: https://codereview.appspot.com/6846138
Patch from Colin Walters <walters@verbum.org>.

ueno/ibus,ueno/ibus,ibus/ibus,ueno/ibus,Keruspe/ibus,ibus/ibus,fujiwarat/ibus,fujiwarat/ibus,ueno/ibus,j717273419/ibus,Keruspe/ibus,ueno/ibus,ibus/ibus,fujiwarat/ibus,j717273419/ibus,Keruspe/ibus,j717273419/ibus,ibus/ibus,j717273419/ibus,fujiwarat/ibus,Keruspe/ibus