title: Add Icons to Layer Control in Leaflet R
body: <p>how to add icons to the layer control in package Leaflet R?.
  I made icons with the following code:</p>
  
  <pre><code>rojos &lt;- makeAwesomeIcon(icon='ion-waterdrop', library='ion', markerColor = 'red', iconColor = 'white')
  verdes &lt;- makeAwesomeIcon(icon='ion-waterdrop', library='ion', markerColor = 'green', iconColor = 'white')
  </code></pre>
  
  <p>and with the following code I made the map</p>
  
  <pre><code>agua &lt;-leaflet(options = leafletOptions(zoomControl = TRUE,
                                          minZoom = 10, maxZoom = 17,
                                          dragging = TRUE))%&gt;%
    addTiles()%&gt;% 
    setView(-101.145,19.793, 10) %&gt;%
    # MAPAS BASE
    addProviderTiles(providers$OpenStreetMap.BlackAndWhite, group = "Calles") %&gt;%
    addProviderTiles(providers$Esri.WorldImagery, group = "Imagen satelital") %&gt;% 
    ###########################################################################################################
  addGeoJSONv2(
    jsonlite::toJSON(rojo),
    markerType="marker",
    markerIcons = rojos,
    popupProperty='popup', 
    labelProperty='NOMBRE DEL CUERPO DE AGUA',
    group = "Agua contaminada") %&gt;%
    addGeoJSONv2(
      jsonlite::toJSON(verde),
      markerType="marker",
      markerIcons = verdes,
      popupProperty='popup', 
      labelProperty='NOMBRE DEL CUERPO DE AGUA',
      group = "Agua no contaminada") %&gt;%
    #POLIGONOS
    addPolygons(data = cuitzeo, col="green",fillColor="Transparent", group = "Cuenca de Cuitzeo",
                weight = 3, opacity = 1)%&gt;%
    addPolygons(data = pol_mor, col="#000000",fillColor="Transparent",  
                group = "Límite Municipal Morelia",
                weight = 2, opacity = 1, fillOpacity = .8) %&gt;%
    # CONTROL DE CAPAS
    addLayersControl(
      baseGroups = c("Calles","Imagen satelital"),
      overlayGroups = c("Agua contaminada","Agua no contaminada","Cuenca de Cuitzeo","Límite Municipal Morelia"),
      options = layersControlOptions(collapsed = F)
    )
  </code></pre>
  
  <p>the result of this is the following:</p>
  
  <p><a href="https://i.stack.imgur.com/w1I6J.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/w1I6J.png" alt="enter image description here"></a></p>
  
  <p>I would like to get something of this style, but with my icons:</p>
  
  <p><a href="https://i.stack.imgur.com/Yihb8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Yihb8.png" alt="enter image description here"></a></p>