MONGOID-5268 Remove JRuby support (#5192)

Co-authored-by: Oleg Pudeyev <[email protected]>

Author: p-mongo

docs/reference/compatibility.txt

@@ -94,7 +94,7 @@ is deprecated.
      -
      -
      -
-     - |checkmark|
+     -
 
    * - 7.4
      - |checkmark|

docs/release-notes/mongoid-8.0.txt

@@ -18,6 +18,12 @@ please consult GitHub releases for detailed release notes and JIRA for
 the complete list of issues fixed in each release, including bug fixes.
 
 
+Ruby Version Support
+--------------------
+
+Mongoid 8.0 removes support for JRuby.
+
+
 Support for MongoDB 3.4 and Earlier Servers Dropped
 ---------------------------------------------------