Fix sphinx error in docstring
Fix sphinx error in docstring

aleksandr-bakanov/astropy,DougBurke/astropy,StuartLittlefair/astropy,larrybradley/astropy,lpsinger/astropy,larrybradley/astropy,pllim/astropy,stargaser/astropy,astropy/astropy,mhvk/astropy,lpsinger/astropy,dhomeier/astropy,DougBurke/astropy,dhomeier/astropy,saimn/astropy,astropy/astropy,astropy/astropy,saimn/astropy,pllim/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,dhomeier/astropy,MSeifert04/astropy,bsipocz/astropy,kelle/astropy,StuartLittlefair/astropy,stargaser/astropy,funbaker/astropy,bsipocz/astropy,mhvk/astropy,kelle/astropy,kelle/astropy,saimn/astropy,AustereCuriosity/astropy,aleksandr-bakanov/astropy,MSeifert04/astropy,larrybradley/astropy,lpsinger/astropy,kelle/astropy,pllim/astropy,larrybradley/astropy,mhvk/astropy,stargaser/astropy,AustereCuriosity/astropy,pllim/astropy,funbaker/astropy,stargaser/astropy,mhvk/astropy,AustereCuriosity/astropy,dhomeier/astropy,aleksandr-bakanov/astropy,lpsinger/astropy,astropy/astropy,saimn/astropy,kelle/astropy,MSeifert04/astropy,larrybradley/astropy,AustereCuriosity/astropy,aleksandr-bakanov/astropy,astropy/astropy,dhomeier/astropy,DougBurke/astropy,funbaker/astropy,AustereCuriosity/astropy,funbaker/astropy,MSeifert04/astropy,StuartLittlefair/astropy,bsipocz/astropy,bsipocz/astropy,pllim/astropy,saimn/astropy,mhvk/astropy,DougBurke/astropy,lpsinger/astropy