Undocumented Zend\Form\FieldsetInterface return type for the Zend\Form\Fieldset::get() method

[nuxwin]

Undocumented return type for the Zend\Form\Fieldset::get() method.

The Zend\Form\Fieldset::get() method can return either a Zend\Form\ElementInterface or Zend\Form\FieldsetInterface. Currently, the Zend\Form\FieldsetInterface return type isn't documented leading to IDE (PhpStorm) inspection error:

Basically

Should look like

[unckleg]

Help wanted ? 🍡
@nuxwin would you make PR for this ?

[nuxwin]

@unckleg

I could yes.