WmsTileLayer example/doc fix

change `format` to `fmt` in example and docstring

Author: njwilson23

examples/Features.ipynb

@@ -145,7 +145,7 @@
     "w = features.WmsTileLayer(\n",
     "    \"http://mesonet.agron.iastate.edu/cgi-bin/wms/nexrad/n0r.cgi\",\n",
     "    name='test',\n",
-    "    format='image/png',\n",
+    "    fmt='image/png',\n",
     "    layers='nexrad-n0r-900913',\n",
     "    attr=u\"Weather data © 2012 IEM Nexrad\",\n",
     "    transparent=True\n",

examples/WMS_and_WMTS.ipynb

@@ -54,7 +54,7 @@
     "    url='http://demo.opengeo.org/geoserver/ows',\n",
     "    layers='nasa:bluemarble',\n",
     "    name='bluemarble',\n",
-    "    format=\"image/png\",\n",
+    "    fmt=\"image/png\",\n",
     ").add_to(m)\n",
     "\n",
     "\n",

folium/features.py

@@ -35,7 +35,7 @@ class WmsTileLayer(Layer):
         The names of the layers to be displayed.
     styles : str, default None
         Comma-separated list of WMS styles.
-    format : str, default None
+    fmt : str, default None
         The format of the service output.
         Ex: 'image/png'
     transparent: bool, default True