Various little changes:

- Add table of content.
- Move references to the top.
- Fix typos.
- Little reformatting.

Author: yakutovicha

00_index.ipynb

@@ -67,7 +67,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.10"
+   "version": "3.10.10"
   }
  },
  "nbformat": 4,