more touch ups to troubleshooting tutorial

new-docs/source/tutorial/3-troubleshooting.ipynb

@@ -125,6 +125,13 @@
     "    print(\"Workflow completed successfully :)\")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Work in progress..."
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -140,14 +147,27 @@
     "Currently in Pydra you need to step backwards through the tasks of the workflow, load\n",
     "the saved task object and inspect its inputs to find the preceding nodes. If any of the\n",
     "inputs that have been generated by previous nodes are not ok, then you should check the\n",
-    "tasks that generated them in turn."
+    "tasks that generated them in turn.\n",
+    "\n",
+    "For example, in the following example if we are not happy with the mask brain that has\n",
+    "been generated, we can check the mask to see whether it looks sensible by first loading\n",
+    "the apply mask task and then inspecting its inputs."
    ]
   },
   {
-   "cell_type": "markdown",
+   "cell_type": "code",
+   "execution_count": null,
    "metadata": {},
+   "outputs": [],
    "source": []
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Work in progress..."
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},