Change the Discount Code label in Easy Digital Downloads

edd_discount_label.php

<?php

function pw_edd_discount_label( $translated_text, $text, $domain ) {

	switch( $translated_text ) {
		case 'Enter discount':
			$translated_text = 'Enter Discount Code Here';
         break;
	}
	
	return $translated_text;
}
add_filter('gettext', 'pw_edd_discount_label', 20, 3);