iterator: Explicitly mention refcounting in docs
iterator: Explicitly mention refcounting in docs

Fixes #585938

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