REST API: Properly capitalize "REST" in translation strings.

Props tobifjellner, sabernhardt, abcd95.
Fixes #63193.



git-svn-id: https://develop.svn.wordpress.org/trunk@60104 602fd350-edb4-49c9-b593-d223f7449a82

Author: audrasjb

src/wp-includes/rest-api.php

@@ -434,7 +434,7 @@ function rest_api_loaded() {
 	if ( ! is_string( $GLOBALS['wp']->query_vars['rest_route'] ) ) {
 		$rest_type_error = new WP_Error(
 			'rest_path_invalid_type',
-			__( 'The rest route parameter must be a string.' ),
+			__( 'The REST route parameter must be a string.' ),
 			array( 'status' => 400 )
 		);
 		wp_die( $rest_type_error );

tests/phpunit/tests/rest-api.php

@@ -2577,7 +2577,7 @@ public function test_should_return_error_if_rest_route_not_string() {
 			rest_api_loaded();
 		} catch ( WPDieException $e ) {
 			$this->assertStringContainsString(
-				'The rest route parameter must be a string.',
+				'The REST route parameter must be a string.',
 				$e->getMessage()
 			);
 			throw $e; // Re-throw to satisfy expectException