TinyMCE: fix directionality settings for RTL languages.

Props westonruter, sa3idho.
Fixes #40972 for trunk.
Built from https://develop.svn.wordpress.org/trunk@40927


git-svn-id: http://core.svn.wordpress.org/trunk@40777 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-editor.php

@@ -826,6 +826,10 @@ final class _WP_Editors {
 		$settings['indent'] = true;
 		$settings['elementpath'] = false;
 
+		if ( is_rtl() ) {
+			$settings['directionality'] = 'rtl';
+		}
+
 		// In production all plugins are loaded (they are in wp-editor.js.gz)
 		// but only these will be initialized by default.
 		$settings['plugins'] = implode( ',', array(

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-40926';
+$wp_version = '4.9-alpha-40927';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.