Update doctrine.rst

Author: ThomasLandauer

doctrine.rst

@@ -735,7 +735,7 @@ Now, you can call this method on the repository::
 
     // ...
 
-If you're in a :ref:`services-constructor-injection`, you can type-hint the
+If you're :ref:`services-constructor-injection`, you can type-hint the
 ``ProductRepository`` class and inject it like normal.
 
 Querying with the Query Builder