Typo: evironment -> environment.

demos/code/code.js

@@ -387,7 +387,7 @@ Code.init = function() {
        zoom: {enabled: true}
       });
 
-  // Add to reserved word list: Local variables in execution evironment (runJS)
+  // Add to reserved word list: Local variables in execution environment (runJS)
   // and the infinite loop detection function.
   Blockly.JavaScript.addReservedWords('code,timeouts,checkTimeout');