Fix typo in doc string
Fix typo in doc string

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