Fix Sphinx warning
Fix Sphinx warning

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