minor symfony#17164 [Lock] Add classes's link (mohamedGasmii)

This PR was merged into the 4.4 branch.

Discussion
----------

[Lock] Add classes's link

Add link to Link and Key classes

<!--

If your pull request fixes a BUG, use the oldest maintained branch that contains
the bug (see https://symfony.com/releases for the list of maintained branches).

If your pull request documents a NEW FEATURE, use the same Symfony branch where
the feature was introduced (and `6.x` for features of unreleased versions).

-->

Commits
-------

2558f61 [Lock] Add classes's link

Author: OskarStark

components/lock.rst

@@ -77,7 +77,7 @@ method can be safely called repeatedly, even if the lock is already acquired.
 Serializing Locks
 ------------------
 
-The ``Key`` contains the state of the ``Lock`` and can be serialized. This
+The :class:`Symfony\\Component\\Lock\\Key` contains the state of the :class:`Symfony\\Component\\Lock\\Lock` and can be serialized. This
 allows the user to begin a long job in a process by acquiring the lock, and
 continue the job in another process using the same lock::