minor #10791 Update associations.rst (beachespecially)

This PR was submitted for the 4.2 branch but it was merged into the 4.1 branch instead (closes #10791).

Discussion
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Update associations.rst

Fixes typo.

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Commits
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f982b42 Update associations.rst

Author: javiereguiluz

doctrine/associations.rst

@@ -136,7 +136,7 @@ not sure of the answer, don't worry! You can always change the settings later:
     >
     (press enter again to finish)
 
-This made changes to *two* changes. First, added a new ``category`` property to
+This made changes to *two* entities. First, it added a new ``category`` property to
 the ``Product`` entity (and getter & setter methods):
 
 .. configuration-block::