Merge pull request #255063 from zzzsyyy/update/xanmod

let

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

  ltsVariant = {

    version = "6.1.52";

    hash = "sha256-uzBmgrjNto2CwqkxdFCPeEPQnPSUZEO2pYMnKe8rCfY=";

    version = "6.1.53";

    hash = "sha256-+70dp+zVOvfKJv9hEy3FpEs2ldrxHiWbokaUnXrNj5o=";

    variant = "lts";

  };

  mainVariant = {

    version = "6.4.15";

    hash = "sha256-WupJJMLqgHJ7FATwNyMwAHIUl9qj0lNH7wRYRBm0CAA=";

    version = "6.5.3";

    hash = "sha256-2giaFyN3kWzQ9cl1mTM9ecSlwoQS+dm3/LvbTAHjZ/A=";

    variant = "main";

  };