fix distributions.rst doctests
fix distributions.rst doctests

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