manual: fix a typo in "Inserting data with appsrc" section
manual: fix a typo in "Inserting data with appsrc" section

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