SERVER-7994: clarifying that timeLockedMicros may be longer than total operation length.

Author: Sam Kleinman

source/reference/database-profiler.txt

@@ -190,7 +190,11 @@ operation.
 
    .. stats:: lockStats.timeLockedMicros
 
-      The time in microseconds the operation held a specific lock.
+      The time in microseconds the operation held a specific lock. For
+      operations that require more than one lock, such as operations
+      that must lock the ``local`` database to update the :term:`oplog`, then
+      this value may be longer than the total length of the
+      operation (i.e. :stats:`millis`.) 
 
    .. stats:: lockStats.timeAcquiringMicros