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

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