Fix reference in docstring
Fix reference in docstring

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