Minor wording fixes
Minor wording fixes

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