DOCSP-28753 fixed authentication mechanism links (#3256)

* DOCSP-28753 update link

* DOCSP-28753 fix link

* DOCSP-28753 fix link

* DOCSP-28753 fix link

Author: jocelyn-mendez1

source/reference/method/db.auth.txt

@@ -137,11 +137,10 @@ The :method:`db.auth()` has the following syntax forms:
 
      - string
 
-     - Optional. The :mongosh:`authentication mechanism
-       <mongosh-shell-authentication-mechanisms>` to use.
+     - Optional. The :option:`authentication mechanism <mongosh --authenticationMechanism>` 
+       to use.
 
-       For available mechanisms, see :mongosh:`authentication mechanisms
-       <mongosh-shell-authentication-mechanisms>`.
+       For available mechanisms, see :option:`authentication mechanisms <mongosh --authenticationMechanism>`.
 
        If unspecified, uses the :dbcommand:`hello` command to determine
        the SASL mechanism or mechanisms for the specified user. See