Added support for array-style callable to FunctionCallDefinitionDumper.

I had a definition failure occur with the following code:

```php
$container->call([$object, 'injectDependencies']);
```

And the dumper failed with the error message:

`ReflectionFunction::__construct() expects parameter 1 to be string, array given`

This PR adds explicit report for array callables to the dumper.