Update modelbuilder_example, writing the illegalcells file in the model folder.ipynb (#1044)

Author: Felix-Deltares

docs/notebooks/modelbuilder_example.ipynb

@@ -1038,7 +1038,7 @@
     "# create and add drypointsfile if there are any cells generated that will result in high orthogonality\n",
     "if len(illegalcells_gdf) > 0:\n",
     "    illegalcells_polyfile = dfmt.geodataframe_to_PolyFile(illegalcells_gdf)\n",
-    "    illegalcells_polyfile.save(\"illegalcells.pol\")\n",
+    "    illegalcells_polyfile.save(os.path.join(dir_output,\"illegalcells.pol\"))\n",
     "    mdu.geometry.drypointsfile = [illegalcells_polyfile]\n",
     "\n",
     "# update numerics settings\n",