docs: fix multiqueue docs for new template names foo_%d -> foo_%u
docs: fix multiqueue docs for new template names foo_%d -> foo_%u

https://bugzilla.gnome.org/show_bug.cgi?id=726358

cablelabs/gstreamer,cablelabs/gstreamer,krichter722/gstreamer,Lachann/gstreamer,cablelabs/gstreamer,surround-io/gstreamer,StreamUtils/gstreamer,surround-io/gstreamer,cfoch/gstreamer,mparis/gstreamer,jpxiong/gstreamer,centricular/gstreamer,krichter722/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,mparis/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,centricular/gstreamer,Lachann/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,jpakkane/gstreamer,jpakkane/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,krichter722/gstreamer,cfoch/gstreamer,surround-io/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,surround-io/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,surround-io/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer,Lachann/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,cablelabs/gstreamer,mparis/gstreamer,centricular/gstreamer,mparis/gstreamer,krichter722/gstreamer,cfoch/gstreamer,jpakkane/gstreamer,cfoch/gstreamer