Add documentation to mt_show_in_cart_fields filter and add ticket t…

…ype argument.

src/mt-cart.php

@@ -993,7 +993,18 @@ function mt_generate_cart_table( $cart, $format = 'cart' ) {
 									$hidden = '';
 								}
 								$total  = $total + ( $price * $count );
-								$custom = apply_filters( 'mt_show_in_cart_fields', '', $event_id );
+								/**
+								 * Show custom fields associated with individual cart items.
+								 *
+								 * @hook mt_show_in_cart_fields
+								 *
+								 * @param {string} $fields HTML output of displayed fields. Default empty.
+								 * @param {int}    $event_id The event currently displayed.
+								 * @param {string} $type The current ticket type.
+								 *
+								 * @return {string}
+								 */
+								$custom = apply_filters( 'mt_show_in_cart_fields', '', $event_id, $type );
 								// Translators: (number of tickets) at (price per ticket).
 								$cart_message = sprintf( __( '%1$s at %2$s', 'my-tickets' ), "<span class='count' data-limit='$max'>$count</span>", apply_filters( 'mt_money_format', $price ) );
 								$output      .= "

src/mt-fields-api.php

@@ -23,7 +23,7 @@ function mt_add_actions() {
 	// Save field data to cookie/user meta for use in cart.
 	add_action( 'mt_add_to_cart_ajax_field_handler', 'mt_handle_custom_field', 10, 2 );
 	// Display field data in shopping cart.
-	add_filter( 'mt_show_in_cart_fields', 'mt_show_custom_field', 10, 2 );
+	add_filter( 'mt_show_in_cart_fields', 'mt_show_custom_field', 10, 3 );
 	// Insert submitted data into Payment post meta.
 	add_action( 'mt_save_payment_fields', 'mt_insert_custom_field', 10, 3 );
 	// Display field data in tickets list.
@@ -245,10 +245,11 @@ function mt_handle_custom_field( $saved, $submit ) {
  *
  * @param string $content Shopping cart html.
  * @param int    $event_id Event ID.
+ * @param string $type Ticket type for this line item.
  *
  * @return string
  */
-function mt_show_custom_field( $content, $event_id ) {
+function mt_show_custom_field( $content, $event_id, $type ) {
 	$custom_fields = mt_get_custom_fields( 'display' );
 	$return        = '';
 	foreach ( $custom_fields as $name => $field ) {