Merge branch 'jc/send-email-sensible-encoding'

"git send-email" used to accept a mistaken "y" (or "yes") as an answer to "What encoding do you want to use [UTF-8]? " without questioning. Now it asks for confirmation when the answer looks too short to be a valid encoding name. * jc/send-email-sensible-encoding: send-email: ask confirmation if given encoding name is very short