Correctly display dataset samples

This takes into account endlines too. Just a visual accuracy change.

optimus/datasets/tinystories.py

@@ -126,5 +126,5 @@ if __name__=='__main__':
         print(f"Sample for '{split}' split:")
         data_loader = DataLoader(dataset, batch_size=1, shuffle=True)
         for data in data_loader:
-            print(data)
+            print(''.join(data))
             break

optimus/datasets/wikitext103.py

@@ -116,5 +116,5 @@ if __name__=='__main__':
         print(f"Sample for '{split}' split:")
         data_loader = DataLoader(dataset, batch_size=1, shuffle=True)
         for data in data_loader:
-            print(data)
+            print(''.join(data))
             break