Unify the variable name in io.fits index docs
Unify the variable name in io.fits index docs

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