Fix minor typo in docs
Fix minor typo in docs

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