chore(docs): update compatibility matrix with SM 3.8

This commit also gets rid of open source column,
as we no longer have such scylla versions, and
we can squeeze old open source versions with
enterprise versions for SM 3.4.

Author: Michal-Leszczynski

docs/source/compatibility-matrix.rst

@@ -1,26 +1,23 @@
 Compatibility Matrix
 ====================
 
-The following table shows which version of Scylla Manager supports which versions of Scylla.
+The following table shows which version of ScyllaDB Manager supports which versions of ScyllaDB.
 
 .. include:: common/restore-raft-schema-warn.rst
 
 .. list-table::
-   :widths: 25 25 25
+   :widths: 25 25
    :header-rows: 1
 
    * - ScyllaDB Manager Version
-     - ScyllaDB Open Source Version
-     - ScyllaDB Enterprise Version
+     - ScyllaDB Version
+   * - 3.8
+     - 2024.1, 2025.1, 2025.2, 2025.3, 2025.4
    * - 3.7
-     -
      - 2024.1, 2025.1, 2025.2, 2025.3, 2025.4
    * - 3.6
-     -
      - 2024.1, 2025.1, 2025.2, 2025.3
    * - 3.5
-     -
      - 2024.1, 2024.2, 2025.1, 2025.2
    * - 3.4
-     - 5.4, 6.0, 6.1, 6.2
-     - 2023.1, 2024.1, 2024.2
+     - 5.4, 6.0, 6.1, 6.2, 2023.1, 2024.1, 2024.2