[monokai theme] Add support for cm-variable-3 type

theme/monokai.css

@@ -20,6 +20,7 @@
 
 .cm-s-monokai span.cm-variable {color: #f8f8f2;}
 .cm-s-monokai span.cm-variable-2 {color: #9effff;}
+.cm-s-monokai span.cm-variable-3 {color: #66d9ef;}
 .cm-s-monokai span.cm-def {color: #fd971f;}
 .cm-s-monokai span.cm-bracket {color: #f8f8f2;}
 .cm-s-monokai span.cm-tag {color: #f92672;}