Merge pull request #257822 from zzzsyyy/update/xanmod

let

  # These names are how they are designated in https://xanmod.org.

  ltsVariant = {

    version = "6.1.54";

    hash = "sha256-sAVWtpR0fzBcLR82MFREG4Qv/JEXyJ+5MZ/XDVE0fu8=";

    version = "6.1.55";

    hash = "sha256-kmiMbzH1hyteicjk1WfCQPYhLsVAbl1t5LJ83rUNZ1k=";

    variant = "lts";

  };

  mainVariant = {

    version = "6.5.4";

    hash = "sha256-zT+aU/pOtKgzVOH5Xg4qd88RcDVBmO4af/rgrkUrnfw=";

    version = "6.5.5";

    hash = "sha256-XjSuhZ5ooXOVllKc29Pd+PlOK6OtcgVMVFzxOx5nkIw=";

    variant = "main";

  };