Fix another an -> a
Fix another an -> a

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