improve cloze and latex tag display in RTL environment

https://anki.tenderapp.com/discussions/ankidesktop/24292-mixed-arabic-and-english-words

web/editor.js

@@ -209,6 +209,10 @@ function maybeDisableButtons() {
 };
 
 function wrap(front, back) {
+    if (currentField.dir == "rtl") {
+        front = "‫" + front + "‬";
+        back = "‫" + back + "‬";
+    }
     var s = window.getSelection();
     var r = s.getRangeAt(0);
     var content = r.cloneContents();