added documentation for python formatters
added documentation for python formatters

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