update docstring to reflect new functionality in Representation.represent_as to support re-representing differentials
update docstring to reflect new functionality in Representation.represent_as to support re-representing differentials

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