Add context to "Discover" when referring to credit card name (#2519)

The Discover credit card payment method needs to be translated differently from the other instances of the word "Discover".

Co-authored-by: Kristófer Reykjalín <[email protected]>

Author: d-alleyne

includes/class-wc-stripe-blocks-support.php

@@ -300,7 +300,7 @@ private function get_icons() {
 		if ( 'USD' === get_woocommerce_currency() ) {
 			$icons_src['discover'] = [
 				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/discover.svg',
-				'alt' => __( 'Discover', 'woocommerce-gateway-stripe' ),
+				'alt' => _x( 'Discover', 'Name of credit card', 'woocommerce-gateway-stripe' ),
 			];
 			$icons_src['jcb']      = [
 				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/jcb.svg',