doc: Remove dropped functions
doc: Remove dropped functions

Dropped in 70a00b8fcc2ca85d3601f6ac4895f906f9032e77

Acked-by: Marc-André Lureau <f20011f729ce65c6b731da6d94357379565098f1@redhat.com>

SPICE/spice-gtk,SPICE/spice-gtk,SPICE/spice-gtk,fgouget/spice-gtk,fgouget/spice-gtk,SPICE/spice-gtk,fgouget/spice-gtk,flexVDI/spice-gtk,flexVDI/spice-gtk