error message typo fix
error message typo fix

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