fix backticks [docs only]
fix backticks [docs only]

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