get-field.txt

Refactor all the code that asks the user a question:
see menu-api.txt

args have trailing space
	mutt_enter_fname_full adds, either of
		" ('?' for list): "
		": "
	mutt_enter_fname calls mutt_enter_fname_full
	mutt_get_field_full prints prompt verbatim
	mutt_get_field calls mutt_get_field_full
		includes both "From: "
		and ":" for :commands
	mutt_pattern_func calls mutt_get_field
		all end ": "
	crypt_ask_for_key calls mutt_get_field
		all ": "
	pgp_ask_for_key calls mutt_get_field
		all ": "
	mutt_get_field_unbuffered calls mutt_get_field
		all ": "
	mutt_get_password calls  mutt_get_field_unbuffered
		some ": "
		some ":" !!!
	edit_address calls mutt_get_field
		all ": "

Check for any leading/trailing space
	(except for alignment)
	Can it be eliminated?