[Fix] enqueueCommand rejections never handled.

Author: SunriseFox

src/client.js

@@ -717,7 +717,7 @@ export default class Client {
     } else if (this._enteredIdle === 'IDLE') {
       this.client.enqueueCommand({
         command: 'IDLE'
-      })
+      }).catch(() => {})
       this._idleTimeout = setTimeout(() => {
         this.client.send('DONE\r\n')
         this._enteredIdle = false