minor symfony#11227 Correct many-to-many to many-to-one (exastion)

This PR was merged into the 3.4 branch.

Discussion
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Correct many-to-many to many-to-one

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Commits
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d7cc365 Correct many-to-many to many-to-one

form/form_collections.rst

@@ -636,7 +636,7 @@ the relationship between the removed ``Tag`` and ``Task`` object.
     ``Tag`` is properly removed.
 
     In Doctrine, you have two sides of the relationship: the owning side and the
-    inverse side. Normally in this case you'll have a many-to-many relationship
+    inverse side. Normally in this case you'll have a many-to-one relationship
     and the deleted tags will disappear and persist correctly (adding new
     tags also works effortlessly).