Update lockable_trait.rst

The method lock() of LockableTrait accept 2 parameters, the first one is the name used to create the lock file, and the second is a value indicating if we should wait until the lock is release. Thus, the line $this->lock(true); should be $this->lock('someRandomLockName', true);

Author: lpussacq

console/lockable_trait.rst

@@ -30,7 +30,7 @@ that adds two convenient methods to lock and release commands::
             }
 
             // If you prefer to wait until the lock is released, use this:
-            // $this->lock(true);
+            // $this->lock('lockname', true);
 
             // ...