Add documentation for the game.state event

docs/events.md

@@ -109,7 +109,7 @@ Allows a player to join a lobby based on the lobby identifier.
 ### Payloads
 Request Payload: `IJoinLobby`
 
-Response Payload: `ILobbyInfo`
+Response Payload: `ILobbyInfo` (or `IGameState` if the game is in progress)
 
 ---
 
@@ -143,3 +143,19 @@ updating the ship design.
 Request Payload: `IUpdatePlayer`
 
 Response Payload: `ServerResponse`
+
+---
+
+## `game.state`
+Provides information about the current game state, used to help keep clients in
+the correct state.
+
+### Supported Event Types
+| Request | Response | Broadcasted
+| ------- | -------- | -----------
+| No      | Yes      | Yes
+
+### Payloads
+Request Payload: N/A
+
+Response Payload: `IGameState`