[lock] fix "time to leave" typo ("time to live")

This fixes a typo in one of the warnings about the TTL for expiring stores where TTL was expanded as *time to leave* instead of *time to live*

Author: MrMitch

components/lock.rst

@@ -478,7 +478,7 @@ Using the above methods, a more robust code would be::
 .. caution::
 
     Choose wisely the lifetime of the ``Lock`` and check whether its remaining
-    time to leave is enough to perform the task.
+    time to live is enough to perform the task.
 
 .. caution::