command /setprefix [<player>] [<text>]:
    usage: &b/prefix プレイヤー つけたい称号
    permission: skript.prefix
    trigger:
        if arg 1 is player:
            if arg 2 is "%arg 2%":
                delete {prefix::%arg 1%::*}
                add arg 2 to {prefix::%arg 1%::*}
                send "&a%player% changed your prefix to %arg 2%&a." to arg 1
                set {prefix.%arg 1%} to true
        if arg 1 is not set:
            send "usage: &b/prefix プレイヤー つけたい称号"