use 2 spaces for tabs

wwwroot/js/site.js

@@ -81,11 +81,11 @@ $(function () {
 
             // set textarea value to: text before caret + tab + text after caret
             $this.val($this.val().substring(0, start)
-                + '\t'
+                + '  '
                 + $this.val().substring(end));
 
             // put caret at right position again
-            this.selectionStart = this.selectionEnd = start + 1;
+            this.selectionStart = this.selectionEnd = start + 2;
 
             // prevent the focus lose
             return false;