reproducing the [model document](https://lms.fun-mooc.fr/asset-v1:inria+41016+self-paced+type@asset+block/toy_notebook_fr.pdf)

produces the same result than tab indentation

* Adjusting the URL l. 11 to be the exact same than in the reference.

* Adding the missing line breaks in subsection 1.

Writing the content of the file following the provided model.

Ce sont en fait des modèles assez universels.