docs: Gram and nit fixes for part-controller.txt
docs: Gram and nit fixes for part-controller.txt

lovebug356/gstreamer,surround-io/gstreamer,ensonic/gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,mparis/gstreamer,cablelabs/gstreamer,cablelabs/gstreamer,cfoch/gstreamer,mparis/gstreamer,jpxiong/gstreamer,lubosz/gstreamer,centricular/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,ensonic/gstreamer,Lachann/gstreamer,lubosz/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,lubosz/gstreamer,shelsonjava/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,jpakkane/gstreamer,jpxiong/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,lovebug356/gstreamer,centricular/gstreamer,cablelabs/gstreamer,ensonic/gstreamer,jpxiong/gstreamer,mparis/gstreamer,cablelabs/gstreamer,krichter722/gstreamer,surround-io/gstreamer,Lachann/gstreamer,surround-io/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,jpxiong/gstreamer,cfoch/gstreamer,cfoch/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,lubosz/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,surround-io/gstreamer,mparis/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,krichter722/gstreamer,centricular/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,centricular/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,jpakkane/gstreamer,lubosz/gstreamer,centricular/gstreamer,surround-io/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,krieger-od/gstreamer,jpakkane/gstreamer,Lachann/gstreamer