DOCSP-30028 added note about rhel server (#278)

Author: kyuan-mongodb

source/core/requirements.txt

@@ -410,7 +410,7 @@ Intel/AMD (``x86_64``) Hardware Architectures
      - 9, 10, 11
      - 10, 11
 
-   * - Red Hat Enterprise Linux / CentOS
+   * - :abbr:`RHEL (Red Hat Enterprise Linux)` / CentOS :sup:`1`
      - 7, 8
      - 7, 8, 9
 
@@ -421,7 +421,9 @@ Intel/AMD (``x86_64``) Hardware Architectures
    * - Ubuntu
      - 18.04, 20.04
      - 18.04, 20.04
-     
+
+:sup:`1` :abbr:`RHEL (Red Hat Enterprise Linux)` is different from :abbr:`RHEL (Red Hat Enterprise Linux)` Server. |mms| supports only :abbr:`RHEL (Red Hat Enterprise Linux)`.
+
 .. note::
 
    Though the {+mdbagent+} can be installed on ``s390x`` and on