Update to-do.md

to-do.md

@@ -19,5 +19,6 @@ Questions:
 - Are there any seasonal trends in the filing of patents?
 - What is the distribution of CPC or IPC labels for patents still marked as pending?
 
-Observation: 1. Fails when the size of the dataset is large.
-             2. Sometimes fails even when the dataset size is small; unreliable!
+Observation:
+1. Fails when the size of the dataset is large.
+2. Sometimes fails even when the dataset size is small; unreliable!