Add setActivity() function

[Nguyenwasd72]

Is your feature request related to a problem? Please describe. No

Describe the solution you'd like Add client.user.setActivity()

Describe alternatives you've considered

// ./bot/main.js
// button:
"<button type=\"button\" onclick=\"window.location.href = `?path=setactivity&activity=${prompt('Activity:')}`\">setActivity</buttton>"
// function:
function setactivity(a) {
    if (a == "null" || a == "") return
    client.user.setActivity(a)
}
module.exports.setactivity = setactivity

// ./server.js
if (r.path === "setactivity" && r.activity) {
    bot.setactivity(r.activity)
    re.send(v + await bot.selectGuild() + style)
}

Additional context I tested the function

Credit Do you want to be credited: Yes Name: KNguyen#8442