NOT a bug!! Just a request for a tiny edit in documentation for renderInput

### I'm Submitting a ...

```
[x ] Bug report
[ ] Feature request
[ ] Support request
```

### Steps to Reproduce

### Expected Results

### Actual Results

### Minimal Reproduction of the Problem

### Other Information (e.g. stacktraces, related issues, suggestions how to fix)
Again, just want to stress that this is not actually a bug, just an omission in the documentation that needs to be added. I wasn't sure how to request edits in the documentation, so created an issue.

The renderInput example has this code:

```
class MyDTPicker extends React.Component {
render(){
return ;
}
renderInput( props, openCalendar, closeCalendar ){
function clear(){
props.onChange({target: {value: ''}});
}
return (

In this (or similar) examples, one should change the line:

`return ;`

to

`return ;`

For functional components, it should be:

`return ;`

Thanks for the great component. I am using it in my project and like the simplicity with the flexibility it offers.