docs(protocol): more auth options [skip ci]

PROTOCOL.md

@@ -39,17 +39,11 @@ interface ConnectionInitMessage {
 }
 ```
 
-The server will respond by either:
-
-- Dispatching a `ConnectionAck` message acknowledging that the connection has been successfully established.
-- Closing the socket with a close event `4403: Forbidden` indicating that the connection request has been denied because of access control.
-- Closing the socket with a close event `4400: <error-message>` indicating that the connection request has been denied because of an implementation specific error.
-
 ### `ConnectionAck`
 
 Direction: **Server -> Client**
 
-Potential response to the `ConnectionInit` message from the client acknowledging a successful connection with the server.
+Expected response to the `ConnectionInit` message from the client acknowledging a successful connection with the server.
 
 ```typescript
 interface ConnectionAckMessage {
@@ -148,24 +142,6 @@ For the sake of clarity, the following examples demonstrate the communication pr
 1. _Server_ validates the connection initialisation request and dispatches a `ConnectionAck` message to the client on successful connection
 1. _Client_ has received the acknowledgement message and is now ready to request operation executions
 
-### Forbidden connection initialisation
-
-1. _Client_ sends a WebSocket handshake request with the sub-protocol: `graphql-transport-ws`
-1. _Server_ accepts the handshake and establishes a WebSocket communication channel (which we call "socket")
-1. _Client_ immediately dispatches a `ConnectionInit` message optionally providing a payload as agreed with the server
-1. _Server_ validates the connection initialisation request and decides that the client is not allowed to establish a connection
-1. _Server_ closes the socket by dispatching the event `4403: Forbidden`
-1. _Client_ reports an error using the close event reason (which is `Forbidden`)
-
-### Erroneous connection initialisation
-
-1. _Client_ sends a WebSocket handshake request with the sub-protocol: `graphql-transport-ws`
-1. _Server_ accepts the handshake and establishes a WebSocket communication channel (which we call "socket")
-1. _Client_ immediately dispatches a `ConnectionInit` message optionally providing a payload as agreed with the server
-1. _Server_ tries validating the connection initialisation request but an error `I'm a teapot` is thrown
-1. _Server_ closes the socket by dispatching the event `4400: I'm a teapot`
-1. _Client_ reports an error using the close event reason (which is `I'm a teapot`)
-
 ### Connection initialisation timeout
 
 1. _Client_ sends a WebSocket handshake request with the sub-protocol: `graphql-transport-ws`
@@ -174,7 +150,6 @@ For the sake of clarity, the following examples demonstrate the communication pr
 1. _Server_ waits for the `ConnectionInit` message for the duration specified in the `connectionInitWaitTimeout` parameter
 1. _Server_ waiting time has passed
 1. _Server_ closes the socket by dispatching the event `4408: Connection initialisation timeout`
-1. _Client_ reports an error using the close event reason (which is `Connection initialisation timeout`)
 
 ### Single result operation