Add missing --mediator-connections-invite cmd arg info to docs

Signed-off-by: Dobrosław Żybort <dobroslaw.zybort@fujitsu.com>

Author: matrixik

Mediation.md

@@ -15,6 +15,7 @@
 
 * `--open-mediation` - Instructs mediators to automatically grant all incoming mediation requests.
 * `--mediator-invitation` - Receive invitation, send mediation request and set as default mediator.
+* `--mediator-connections-invite` - Connect to mediator through a connection invitation. If not specified, connect using an OOB invitation.
 * `--default-mediator-id` - Set pre-existing mediator as default mediator.
 * `--clear-default-mediator` - Clear the stored default mediator.
 
@@ -72,4 +73,4 @@ See [Aries RFC 0211: Coordinate Mediation Protocol](https://github.com/hyperledg
 ## Using a Mediator
 
 After establishing a connection with a mediator also having mediation granted, you can use that mediator id for future did_comm connections.
- When creating, receiving or accepting a invitation intended to be Mediated, you provide `mediation_id` with the desired mediator id. if using a single mediator for all future connections, You can set a default mediation id. If no mediation_id is provided the default mediation id will be used instead.
+ When creating, receiving or accepting a invitation intended to be Mediated, you provide `mediation_id` with the desired mediator id. if using a single mediator for all future connections, You can set a default mediation id. If no mediation_id is provided the default mediation id will be used instead.