How to merge csscomb.preset

[yingyuk]

Environment

• VSCode Version: 1.20.1

Actual behavior

 "csscomb.preset": {
    "sort-order": [
      [
        "$variable"
      ],
      [
        "$include"
      ],
      [
        "$include media"
      ]
    ]
  }

Expected behavior

 "csscomb.preset": "zen",
 "csscomb.customPreset": {
    "sort-order": [
      [
        "$variable"
      ],
      [
        "$include"
      ],
      [
        "$include media"
      ]
    ]
  }

Object.assign(csscomb.preset, csscomb.customPreset)