docs(lock): fix typo in symfony lock documentation

Author: JacquesDurand

lock.rst

@@ -190,7 +190,7 @@ Locking a Dynamic Resource
 
 Sometimes the application is able to cut the resource into small pieces in order
 to lock a small subset of process and let other through. In our previous example
-with see how to lock the ``$pdf->getOrCreatePdf('terms-of-use')`` for everybody,
+we've seen how to lock the ``$pdf->getOrCreatePdf('terms-of-use')`` for everybody,
 now let's see how to lock ``$pdf->getOrCreatePdf($version)`` only for
 processes asking for the same ``$version``::