minor #4053 Update doctrine.rst (sr972)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #4053).

Discussion
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Update doctrine.rst

| Q             | A
| ------------- | ---
| Doc fix?      | [yes]
| New docs?     | [no]
| Applies to    | [2.3+]

In 'Deleting an Object' you are not going to delete the entity itself but the given object.

Commits
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b269ff0 Update doctrine.rst

Author: weaverryan

book/doctrine.rst

@@ -699,7 +699,7 @@ method of the entity manager::
     $em->flush();
 
 As you might expect, the ``remove()`` method notifies Doctrine that you'd
-like to remove the given entity from the database. The actual ``DELETE`` query,
+like to remove the given object from the database. The actual ``DELETE`` query,
 however, isn't actually executed until the ``flush()`` method is called.
 
 .. _`book-doctrine-queries`: