minor #3465 change wording in versionadded example to be consistent w…

…ith what we use... (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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change wording in versionadded example to be consistent with what we use...

... today

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets |

Commits
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f35152b change wording in versionadded example to be consistent with what we use today

contributing/documentation/overview.rst

@@ -135,7 +135,7 @@ tag and a short description:
 .. code-block:: text
 
     .. versionadded:: 2.3
-        The ``askHiddenResponse`` method was added in Symfony 2.3.
+        The ``askHiddenResponse`` method was introduced in Symfony 2.3.
 
     You can also ask a question and hide the response. This is particularly...