Update notebook markdown texts

Pitfall2-Example.ipynb

@@ -36,7 +36,7 @@
    "metadata": {},
    "source": [
     "# Creating a dataset\n",
-    "We create a $G_{n,p}$ random graph with $n=20$ and $p=0.2$. Initially the color for all nodes are blue (constant feature=1). We randomly select 3 nodes and assign them the color yellow(feature=0) such that there is at most on edge between two yellow nodes, therefore the explanation is unique. The task is to classify whether a graph has an edge between two yellow nodes or not."
+    "We create a $G_{n,p}$ random graph with $n=20$ and $p=0.2$. Initially the color for all nodes are blue (constant feature=1). We randomly select 3 nodes and assign them the color yellow(feature=2) such that there is at most on edge between two yellow nodes, therefore the explanation is unique. The task is to classify whether a graph has an edge between two yellow nodes or not."
    ]
   },
   {