make client.readyTime a date

src/client/Client.js

@@ -99,8 +99,8 @@ class Client extends EventEmitter {
      */
     this.password = null;
     /**
-     * The time in milliseconds the Client connected
-     * @type {?number}
+     * The date at which the Client was regarded as being in the `READY` state.
+     * @type {?Date}
      */
     this.readyTime = null;
     this._intervals = [];

src/client/websocket/packets/handlers/Ready.js

@@ -10,7 +10,7 @@ class ReadyHandler extends AbstractHandler {
 
     const clientUser = new ClientUser(client, data.user);
     client.user = clientUser;
-    client.readyTime = Date.now();
+    client.readyTime = new Date();
     client.users.set(clientUser.id, clientUser);
 
     for (const guild of data.guilds) client.dataManager.newGuild(guild);