docs: fix example to use a category name that actually exists
docs: fix example to use a category name that actually exists

jpakkane/gstreamer,ahmedammar/platform_external_gst_gstreamer,cfoch/gstreamer,StreamUtils/gstreamer,mrchapp/gstreamer,lovebug356/gstreamer,ensonic/gstreamer,krichter722/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,magcius/gstreamer,mrchapp/gstreamer,krieger-od/gstreamer,drothlis/gstreamer,justinjoy/gstreamer,mparis/gstreamer,ensonic/gstreamer,magcius/gstreamer,krichter722/gstreamer,drothlis/gstreamer,ylatuya/gstreamer,ahmedammar/platform_external_gst_gstreamer,Distrotech/gstreamer,mrchapp/gstreamer,cablelabs/gstreamer,cablelabs/gstreamer,cablelabs/gstreamer,centricular/gstreamer,ahmedammar/platform_external_gst_gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,krichter722/gstreamer,mparis/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,lubosz/gstreamer,Distrotech/gstreamer,mrchapp/gstreamer,justinjoy/gstreamer,jpakkane/gstreamer,ahmedammar/platform_external_gst_gstreamer,jpakkane/gstreamer,krieger-od/gstreamer,surround-io/gstreamer,surround-io/gstreamer,justinjoy/gstreamer,drothlis/gstreamer,magcius/gstreamer,jpakkane/gstreamer,ensonic/gstreamer,magcius/gstreamer,shelsonjava/gstreamer,magcius/gstreamer,shelsonjava/gstreamer,justinjoy/gstreamer,cfoch/gstreamer,StreamUtils/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,ylatuya/gstreamer,surround-io/gstreamer,Distrotech/gstreamer,lubosz/gstreamer,cfoch/gstreamer,centricular/gstreamer,cfoch/gstreamer,krichter722/gstreamer,surround-io/gstreamer,mparis/gstreamer,collects/gstreamer,drothlis/gstreamer,krichter722/gstreamer,lubosz/gstreamer,jpxiong/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,surround-io/gstreamer,lovebug356/gstreamer,mparis/gstreamer,ylatuya/gstreamer,Distrotech/gstreamer,ylatuya/gstreamer,ahmedammar/platform_external_gst_gstreamer,ensonic/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,mparis/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,lubosz/gstreamer,Distrotech/gstreamer,justinjoy/gstreamer,lubosz/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,mrchapp/gstreamer,Lachann/gstreamer,ylatuya/gstreamer,Lachann/gstreamer,collects/gstreamer,shelsonjava/gstreamer,collects/gstreamer,drothlis/gstreamer,collects/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,collects/gstreamer,centricular/gstreamer,centricular/gstreamer,Lachann/gstreamer,krieger-od/gstreamer