Fix sphinx warnings
Fix sphinx warnings

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