minor #19697 [Console] Add doc about lockableTrait (VincentLanglet)

This PR was squashed before being merged into the 7.1 branch.

Discussion
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[Console] Add doc about lockableTrait

Closes #19688

Commits
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1aab03d [Console] Add doc about lockableTrait

Author: javiereguiluz

console/lockable_trait.rst

@@ -43,4 +43,24 @@ that adds two convenient methods to lock and release commands::
         }
     }
 
+The LockableTrait will use the ``SemaphoreStore`` if available and will default
+to ``FlockStore`` otherwise. You can override this behavior by setting
+a ``$lockFactory`` property with your own lock factory::
+
+    // ...
+    use Symfony\Component\Console\Command\Command;
+    use Symfony\Component\Console\Command\LockableTrait;
+    use Symfony\Component\Lock\LockFactory;
+
+    class UpdateContentsCommand extends Command
+    {
+        use LockableTrait;
+
+        public function __construct(private LockFactory $lockFactory)
+        {
+        }
+
+        // ...
+    }
+
 .. _`locks`: https://en.wikipedia.org/wiki/Lock_(computer_science)