[feat] TrailingCommaInMultiLineArrayFixer

|Q            |A  |
|---          |---|
|Bug Fix?     |n  |
|New Feature? |yes|
|BC Breaks?   |n  |
|Deprecations?|n  |
|Tests Pass?  |yes|
|Fixed Tickets|   |
|License      |MIT|
|Doc PR       |   |
                   

This adds the TrailingCommaInMultiLineArrayFixer: PHP Multi-line arrays should have a trailing comma

There is only minor problem that I was unable to resolve, when you have an array like.

```php
<?php

$x = array(
    array());

?>
```

The result will be.

```php
<?php

$x = array(
    array(),);

?>
```

Which is not fully correct, but the detection for this is problamatic.

We can't just add a new line, as that will move the closing brace to the beginging of the line.
And looking for the previous whitespace as something like `($y ? 'yes' : 'no')` will detect the wrong whitespace for indenting.

So we can either detect the missing new-line and add it, and let a nother fixer (or manual change) fix this.
Or leave this as it is now, and try to fix this later using either another fixer or improving this fixer.

Sent using [Gush](https://github.com/gushphp/gush)
OK. So you know that after inserting a new Token the collection size changed and you need to change iteration limit.

So let see what is going on now.
1. In `fixArray` method you call `fixArray` method (ugly recursion IMO ;) ), which may or may not change collection size - so you recalculate `$c`. So we don't know what actually happend, so recalculate to be sure...
2. In `fix` method you call `fixArray` method, which also may change collection size - but here you do not recalculate `$c` - if we have code with hundreds of multi-line array and all of them need to be fixed - the last one will stay intact :(

IMO you should iterate backward, then adding tokens after current iterator causes no harm. Like here: https://github.com/fabpot/PHP-CS-Fixer/blob/master/Symfony/CS/Fixer/Contrib/ConcatWithSpaces.php#L27