Added the right single quotation mark to diactritics. (#4337)

It should be simplified to a typewriter apostrophe.

src/js/select2/diacritics.js

@@ -842,7 +842,8 @@ define([
     '\u03CB': '\u03C5',
     '\u03B0': '\u03C5',
     '\u03C9': '\u03C9',
-    '\u03C2': '\u03C3'
+    '\u03C2': '\u03C3',
+    '\u2019': '\''
   };
 
   return diacritics;