Add a clarifying note for OLM: mention OpenShift (#11) (#16)

We received a question asking for migration guide for OpenShift users.
This change makes it a bit more clear that OLM part applies to
OpenShift users.

(cherry picked from commit 954416a)

Co-authored-by: Mikalai Radchuk <[email protected]>

Author: jwilliams-mongo

source/tutorial/migrate-to-mck.txt

@@ -25,8 +25,8 @@ Migrate from MongoDB Enterprise Operator to |k8s-op-short| for Most Deployments
 -------------------------------------------------------------------------------
 
 Follow these steps to migrate in most deployment scenarios. If you are using
-Operator Lifecycle Manager (OLM) to manage 
-your operator deployments, see :ref:`these steps <migrate-mck-olm>` instead.
+Operator Lifecycle Manager (OLM) to manage your operator deployments 
+(typically on OpenShift clusters), see :ref:`these steps <migrate-mck-olm>` instead.
 
 .. procedure::
    :style: normal
@@ -115,10 +115,11 @@ your operator deployments, see :ref:`these steps <migrate-mck-olm>` instead.
 
 .. _migrate-mck-olm:
 
-Migrate from MongoDB Enterprise Kubernetes Operator to |k8s-op-short| with the Operator Lifecycle Manager (OLM)
+Migrate from MongoDB Enterprise Kubernetes Operator to |k8s-op-short| with the Operator Lifecycle Manager (OLM) on OpenShift or Other Platforms
 ---------------------------------------------------------------------------------------------------------------
 
-To migrate from the MongoDB Enterprise Kubernetes Operator to the |k8s-op-short| using OLM, 
+To migrate from the MongoDB Enterprise Kubernetes Operator to the |k8s-op-short| using OLM
+(the typical deployment method on OpenShift clusters, but also possible on other Kubernetes platforms),
 uninstall the old operator and then install the new one:
 
 .. important::