(DOCSP-45763) [MIG] Add downloads page link to release notes (#185)

* (DOCSP-45763) Add download link to release notes.

* (DOCSP-45763) Condense text.

Author: elyse-mdb

source/release-notes.txt

@@ -10,6 +10,8 @@ Release Notes
    :depth: 1
    :class: twocols
 
+Download the latest Relational Migrator binary from the `release page <https://www.mongodb.com/try/download/relational-migrator>`__. 
+For installation instructions, see the :ref:`Installation <installation>` page. 
 
 1.11.0 Changelog
 ----------------