minor symfony#9014 add default option value for collection type (xabbuh)

This PR was merged into the 2.7 branch.

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add default option value for collection type

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96f608a add default option value for collection type

Author: javiereguiluz

reference/forms/types/collection.rst

@@ -357,7 +357,7 @@ not replaced with the same value.
 type
 ~~~~
 
-**type**: ``string`` or :class:`Symfony\\Component\\Form\\FormTypeInterface` **required**
+**type**: ``string`` or :class:`Symfony\\Component\\Form\\FormTypeInterface` **default**: ``text``
 
 This is the field type for each item in this collection (e.g. ``text``,
 ``choice``, etc). For example, if you have an array of email addresses,