Fix small error in SingleHue documentation
Fix small error in SingleHue documentation

sh4wn/vispy,ghisvail/vispy,michaelaye/vispy,srinathv/vispy,QuLogic/vispy,sh4wn/vispy,kkuunnddaannkk/vispy,Eric89GXL/vispy,RebeccaWPerry/vispy,Eric89GXL/vispy,jdreaver/vispy,hronoses/vispy,RebeccaWPerry/vispy,QuLogic/vispy,RebeccaWPerry/vispy,michaelaye/vispy,julienr/vispy,drufat/vispy,Eric89GXL/vispy,dchilds7/Deysha-Star-Formation,sbtlaarzc/vispy,bollu/vispy,bollu/vispy,inclement/vispy,ghisvail/vispy,drufat/vispy,dchilds7/Deysha-Star-Formation,inclement/vispy,inclement/vispy,sbtlaarzc/vispy,drufat/vispy,bollu/vispy,QuLogic/vispy,ghisvail/vispy,julienr/vispy,kkuunnddaannkk/vispy,sh4wn/vispy,hronoses/vispy,sbtlaarzc/vispy,jay3sh/vispy,michaelaye/vispy,srinathv/vispy,julienr/vispy,dchilds7/Deysha-Star-Formation,hronoses/vispy,jdreaver/vispy,jay3sh/vispy,jay3sh/vispy,srinathv/vispy,kkuunnddaannkk/vispy,jdreaver/vispy