fix sphinx warnings
fix sphinx warnings

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