common/lz.c: improve lz_encode comment
common/lz.c: improve lz_encode comment

SPICE/spice-common,elmarco/spice-common,fgouget/spice-common,freedesktop-unofficial-mirror/spice__spice-common,Fantu/spice-common,Fantu/spice-common,Fantu/spice-common,elmarco/spice-common,elmarco/spice-common,freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,freedesktop-unofficial-mirror/spice__spice-common,SPICE/spice-common,elmarco/spice-common,fgouget/spice-common,freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,Fantu/spice-common,SPICE/spice-common