chore: updated yml

Author: eni-awowale

_toc.yml

@@ -18,7 +18,7 @@ parts:
           - file: fundamentals/01_datastructures
           - file: fundamentals/01.1_creating_data_structures
           - file: fundamentals/01.1_io
-          - file: fundamentals/01_datatree_imerghh.ipynb
+          - file: fundamentals/01_datatree_hierarchical_data.ipynb
       - file: fundamentals/02_labeled_data.md
         sections:
           - file: fundamentals/02.1_indexing_Basic.ipynb