TinyMCE: fix (switch) the indent/outdent icons in RTL mode so the arrow points at the proper direction. Props avryl, fixes #21281.

git-svn-id: https://develop.svn.wordpress.org/trunk@31142 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/css/editor.css

@@ -884,6 +884,15 @@ i.mce-i-hr:before {
 	content: '\f475';
 }
 
+/* RTL button icons */
+.rtl i.mce-i-outdent:before {
+	content: '\f222';
+}
+
+.rtl i.mce-i-indent:before {
+	content: '\f221';
+}
+
 /* Editors */
 .wp-editor-wrap {
 	position: relative;