🎨 remove headings ( toc tree is not included in overview)

Author: enryH

docs/index.md

@@ -6,7 +6,7 @@
 :relative-images:
 ```
 
-## Tutorial
+<!-- hidden toc trees for sidebar -->
 
 ```{toctree}
 :maxdepth: 2
@@ -16,8 +16,6 @@
 tutorial/tutorial
 ```
 
-## Contents
-
 ```{toctree}
 :maxdepth: 2
 :caption: "Reference"
@@ -26,8 +24,6 @@ tutorial/tutorial
 reference/python_package
 ```
 
-## Technical notes
-
 ```{toctree}
 :maxdepth: 2
 :caption: "Technical notes"