DOCS-15333-dbhash-locking (#1473) (#1494)

Co-authored-by: jason-price-mongodb <[email protected]>

Co-authored-by: jason-price-mongodb <[email protected]>

Author: jason-price-mongodb

source/reference/command/dbHash.txt

@@ -20,6 +20,9 @@ Definition
    to compare databases across :binary:`~bin.mongod` instances, such as
    across members of replica sets.
 
+   The :dbcommand:`dbHash` command obtains a shared (S) lock on the
+   database, which prevents writes until the command completes.
+
    :dbcommand:`dbHash` has the following syntax:
 
    .. code-block:: javascript