REST API: Use a consistent description for the textdomain schema property between plugins and themes controllers.

Follow-up to [48242], [48627].

Props audrasjb.
Fixes #50776. See #50321.

git-svn-id: https://develop.svn.wordpress.org/trunk@48628 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/rest-api/endpoints/class-wp-rest-themes-controller.php

@@ -367,7 +367,7 @@ class WP_REST_Themes_Controller extends WP_REST_Controller {
 					),
 				),
 				'textdomain'     => array(
-					'description' => __( 'The theme\'s textdomain.' ),
+					'description' => __( 'The theme\'s text domain.' ),
 					'type'        => 'string',
 					'readonly'    => true,
 				),