chore(core): document gateway

Author: didinele

packages/core/src/Gateway.ts

@@ -2,11 +2,20 @@ import type { Awaitable } from '@discordjs/util';
 import type { ManagerShardEventsMap, WebSocketShardEvents } from '@discordjs/ws';
 import type { GatewaySendPayload } from 'discord-api-types/v10';
 
+/**
+ * A Discord gateway-like interface that can be used to send & recieve events.
+ */
 export interface Gateway {
+	/**
+	 * Gets how many shards your bot is running.
+	 */
 	getShardCount(): Awaitable<number>;
 	on(
 		event: WebSocketShardEvents.Dispatch,
 		listener: (...params: ManagerShardEventsMap[WebSocketShardEvents.Dispatch]) => Awaitable<void>,
 	): this;
+	/**
+	 * Sends a payload to the specified shard
+	 */
 	send(shardId: number, payload: GatewaySendPayload): Awaitable<void>;
 }