export text to geojson

[3xxx]

{
    "type": "Feature",
    "properties":
    {
      "textMarker": true,
      "text": "测试文字1",
      "icon":
      {
        "options":
        {
          "className": "pm-text-marker",
          "html":
          {
            "_leaflet_id": 230
          }
        },
        "_initHooksCalled": true
      },
      "type": "marker"
    },
    "geometry":
    {
      "type": "Point",
      "coordinates": [113.305435, 23.125837]
    }
  },