Mapbox GL JS:在图层上方显示地图标签？

var map = new mapboxgl.Map({
  container: 'map',
  style: 'mapbox://styles/mapbox/streets-v11',
  center: [lng, lat],
  zoom: zoomLevel
});

map.on('load', function() {
  map.addLayer({
    id: 'labels',
    type: 'symbol',
    source: {
      type: 'geojson',
      data: {
        type: 'FeatureCollection',
        features: [{
          type: 'Feature',
          geometry: {
            type: 'Point',
            coordinates: [lng, lat]
          },
          properties: {
            title: '标签标题',
            description: '标签描述'
          }
        }]
      }
    },
    layout: {
      'text-field': ['get', 'title'],
      'text-font': ['Open Sans Regular'],
      'text-size': 12,
      'text-anchor': 'top'
    },
    paint: {
      'text-color': '#000000'
    }
  });
});