DOCS-9832: update uri readConcernLevel

Author: kay-kim

source/reference/connection-string.txt

@@ -441,8 +441,12 @@ isolation for their reads from replica sets.
 
    * - .. urioption:: readConcernLevel
 
-     - The level of isolation. Accepts either :readconcern:`"local"` or
-       :readconcern:`"majority"`.
+     - The level of isolation. Accepts:
+     
+       - :readconcern:`local <"local">`
+       - :readconcern:`majority <"majority">`
+       - :readconcern:`linearizable <"linearizable">`
+       - :readconcern:`available <"available">`
 
        For details, see :doc:`/reference/read-concern`.