DOCS-4986 highlight the all uppercase statement for kerberos/windows

Author: kay-kim

source/includes/steps-control-access-to-mongodb-windows-with-kerberos-authentication.yaml

@@ -25,7 +25,7 @@ ref: add-kerberos-principals-windows
 pre: |
    Add a Kerberos principal, ``<username>@<KERBEROS REALM>``, to
    MongoDB in the ``$external`` database. Specify the Kerberos realm in
-   all uppercase. The ``$external`` database allows
+   **ALL UPPERCASE**. The ``$external`` database allows
    :program:`mongod.exe` to consult an external source (e.g. Kerberos)
    to authenticate. To specify the user's privileges, assign
    :doc:`roles </core/authorization>` to the user.