**Do you want to request a _feature_ or report a _bug_?**
Enhancement

**What is the current behavior?**
Element type checker is not as informative as the other ones.

**What is the expected behavior?**
It would be nice to provide the actual type of the prop passed similarly to other type checkers. I.e., instead of 

> Invalid prop `Prop` supplied to `Component`, expected a single ReactElement.

say

> Invalid prop `Prop` of type `type` supplied to `Component`, expected a single ReactElement.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
Seeing this on 15.2.1 but I think it's also applicable to previous versions.

I know the general intention is to move away from prop types, but if there isn't a specific reason for the current behavior I can look into making this more pretty.

/**
 * Copyright 2013-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule ReactPropTypes
 */
'use strict';
var ReactElement = require('ReactElement');
var ReactPropTypeLocationNames = require('ReactPropTypeLocationNames');
var ReactPropTypesSecret = require('ReactPropTypesSecret');
var emptyFunction = require('emptyFunction');
var getIteratorFn = require('getIteratorFn');
var warning = require('warning');
/**
 * Collection of methods that allow declaration and validation of props that are
 * supplied to React components. Example usage:
 *
 *   var Props = require('ReactPropTypes');
 *   var MyArticle = React.createClass({
 *     propTypes: {
 *       // An optional string prop named "description".
 *       description: Props.string,
 *