minor #12002 Use string instead of FQCN (OskarStark)

This PR was merged into the 3.4 branch.

Discussion
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Use string instead of FQCN

If the type is string, it should either be:

**type**: ``string`` **default**: ``'Symfony\Component\Form\Extension\Core\Type\TextType'``

or

**type**: ``string`` **default**: ``Symfony\Component\Form\Extension\Core\Type\TextType::class``

@xabbuh can you please give me some feedback here? Thanks

Commits
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0c26a3d Use string instead of FQCN

Author: OskarStark

reference/forms/types/collection.rst

@@ -323,7 +323,7 @@ type::
 entry_type
 ~~~~~~~~~~
 
-**type**: ``string`` **default**: ``Symfony\\Component\\Form\\Extension\\Core\\Type\\TextType``
+**type**: ``string`` **default**: ``'Symfony\Component\Form\Extension\Core\Type\TextType'``
 
 This is the field type for each item in this collection (e.g. ``TextType``,
 ``ChoiceType``, etc). For example, if you have an array of email addresses,