update description of warnings to include the clarifications @embray suggested
update description of warnings to include the clarifications @embray suggested

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