Update wfs-referencing.ipynb

explicite marker and linestyle

Author: fs446

doc/examples/wfs-referencing.ipynb

@@ -62,7 +62,8 @@
     "                                tapering_window,\n",
     "                                size=0.125, ax=axs[i])\n",
     "        axs[i].plot(xref[:, 0][selection],\n",
-    "                    xref[:, 1][selection], 'o', color='dimgray', ms=4)\n",
+    "                    xref[:, 1][selection],\n",
+    "                    marker='o', linestyle='', color='dimgray', ms=4)\n",
     "        axs[i].grid(True)\n",
     "    plt.tight_layout()\n",
     "    return p\n"