Rename to match attribute and __repr__
Rename to match attribute and __repr__

In constant.py, rename units -> unit and error -> uncertainty to match __repr__ to attributes.
dhomeier/astropy,larrybradley/astropy,funbaker/astropy,mhvk/astropy,DougBurke/astropy,pllim/astropy,AustereCuriosity/astropy,lpsinger/astropy,MSeifert04/astropy,kelle/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,mhvk/astropy,joergdietrich/astropy,stargaser/astropy,AustereCuriosity/astropy,saimn/astropy,joergdietrich/astropy,DougBurke/astropy,larrybradley/astropy,astropy/astropy,pllim/astropy,kelle/astropy,saimn/astropy,pllim/astropy,astropy/astropy,stargaser/astropy,DougBurke/astropy,lpsinger/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,StuartLittlefair/astropy,mhvk/astropy,DougBurke/astropy,StuartLittlefair/astropy,kelle/astropy,stargaser/astropy,aleksandr-bakanov/astropy,saimn/astropy,lpsinger/astropy,dhomeier/astropy,joergdietrich/astropy,pllim/astropy,mhvk/astropy,StuartLittlefair/astropy,joergdietrich/astropy,bsipocz/astropy,dhomeier/astropy,funbaker/astropy,bsipocz/astropy,bsipocz/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,StuartLittlefair/astropy,lpsinger/astropy,astropy/astropy,bsipocz/astropy,pllim/astropy,dhomeier/astropy,tbabej/astropy,larrybradley/astropy,kelle/astropy,funbaker/astropy,mhvk/astropy,funbaker/astropy,AustereCuriosity/astropy,tbabej/astropy,tbabej/astropy,stargaser/astropy,MSeifert04/astropy,kelle/astropy,larrybradley/astropy,tbabej/astropy,AustereCuriosity/astropy,astropy/astropy,StuartLittlefair/astropy,astropy/astropy,tbabej/astropy,saimn/astropy,saimn/astropy,joergdietrich/astropy,AustereCuriosity/astropy,lpsinger/astropy,dhomeier/astropy