/**
* Flattens the structure of form elements.
*
- * If a form element has #flatten = TRUE, then all of it's children get moved
+ * If a form element has #flatten = TRUE, then all of its children get moved
* to the same level as the element itself. So $form['to_be_flattened'][$key]
* becomes $form[$key], and $form['to_be_flattened'] gets unset.
*