**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.

if (__DEV__) {
    var manualPropTypeCallCache = {};
  }
  function checkType(
    isRequired,
    props,
    propName,
    componentName,
    location,
    propFullName,
    secret
  ) {
    componentName = componentName || ANONYMOUS;
    propFullName = propFullName || propName;
    if (__DEV__) {
      if (
        secret !== ReactPropTypesSecret &&
        typeof console !== 'undefined'
      ) {
        var cacheKey = `${componentName}:${propName}`;
        if (!manualPropTypeCallCache[cacheKey]) {
          warning(
            false,
            'You are manually calling a React.PropTypes validation ' +
            'function for the `%s` prop on `%s`. This is deprecated ' +
            'and will not work in the next major version. You may be ' +
            'seeing this warning due to a third-party PropTypes library. ' +
            'See https://fb.me/react-warning-dont-call-proptypes for details.',
            propFullName,