REST API: Allow fetching multiple terms at once via the slug parameter.

This matches a similar change previously made for posts (#38579) and an upcoming change for users (#40213).

Props wonderboymusic, MatheusGimenez, curdin.
Fixes #40027.

Merges [40376] to the 4.7 branch.

Built from https://develop.svn.wordpress.org/branches/4.7@40427


git-svn-id: http://core.svn.wordpress.org/branches/4.7@40325 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php

@@ -979,7 +979,10 @@ class WP_REST_Terms_Controller extends WP_REST_Controller {
 
 		$query_params['slug'] = array(
 			'description'       => __( 'Limit result set to terms with a specific slug.' ),
-			'type'              => 'string',
+			'type'              => 'array',
+			'items'             => array(
+				'type'          => 'string'
+			),
 		);
 
 		/**

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7.4-alpha-40426';
+$wp_version = '4.7.4-alpha-40427';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.