`pinlast`: Automatically unpin the previous message after some time.

    You must have the Manage Messages permission to use this command.

    Messages pinned using the `pinlast` command are automatically unpinned after
    a specified duration. Because the bot also handles the initial pinning as
    well, Discord will only state that the bot pinned the message, so the user
    who truly pinned the message is recorded by the bot.

    **Usage:**
        `pinlast for TIME`: Pin the last message for TIME amount of time.
        `pinlast list`: List all pinned messages tracked by the bot.
        `pinlast stop ID`: Stop tracking a pinned message. ID is from `list`.
        `pinlast update ID TIME`: Change when a message will be unpinned.

    **Time format:**
        Use numbers followed by a single letter for denoting the unit of time.
        `5w 4d 3h 2m 1s` represents 5 weeks, 4 days, 3 hours, 2 minutes, 1 sec
        from now. Any of these fields are optional, so you can just specify `1h`
        for 1 hour if you wish.