Update angular.toJson externs to allow `number` type as the second parameter
See
@@ -200,7 +200,7 @@ angular.reloadWithDebugInfo = function() {};
/**
* @param {Object|Array|Date|string|number|boolean} obj
- * @param {boolean=} opt_pretty
+ * @param {number|boolean=} opt_pretty
* @return {string}
*/
angular.toJson = function(obj, opt_pretty) {};
