I18N: Move code out of a translatable string in `WP_REST_Posts_Contro…

…ller::get_item_schema()`.

Props ramiy.
Fixes #50759.

git-svn-id: https://develop.svn.wordpress.org/trunk@48610 602fd350-edb4-49c9-b593-d223f7449a82

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

@@ -2192,6 +2192,7 @@ public function get_item_schema() {
 				'custom-fields',
 			),
 		);
+
 		foreach ( $post_type_attributes as $attribute ) {
 			if ( isset( $fixed_schemas[ $this->post_type ] ) && ! in_array( $attribute, $fixed_schemas[ $this->post_type ], true ) ) {
 				continue;
@@ -2424,7 +2425,15 @@ public function get_item_schema() {
 		// Emit a _doing_it_wrong warning if user tries to add new properties using this filter.
 		$new_fields = array_diff( array_keys( $schema['properties'] ), $schema_fields );
 		if ( count( $new_fields ) > 0 ) {
-			_doing_it_wrong( __METHOD__, __( 'Please use register_rest_field to add new schema properties.' ), '5.4.0' );
+			_doing_it_wrong(
+				__METHOD__,
+				sprintf(
+					/* translators: %s: register_rest_field */
+					__( 'Please use %s to add new schema properties.' ),
+					'<code>register_rest_field<code>'
+				),
+				'5.4.0'
+			);
 		}
 
 		$this->schema = $schema;