Plot of predictions with test data in Colab notebook doesn't make much sense

In the Colab notebook, after the training we plot some graphs.
The last one, which is "Plot the predictions along with to the test data", is literally taken from a standard TensorFlow Lite example notebook (see https://colab.research.google.com/github/tensorflow/tensorflow/blob/master/tensorflow/lite/experimental/micro/examples/hello_world/create_sine_model.ipynb#scrollTo=L_vE-ZDkHVxe )
but does not make much sense in this context.

Besides that, the code for that plot currently (ab)uses a deprecated matplotlib behaviour
```
/usr/local/lib/python3.6/dist-packages/matplotlib/axes/_base.py:380: MatplotlibDeprecationWarning:
cycling among columns of inputs with non-matching shapes is deprecated.
```
which also suggests that the current plot is a bit nonsensical.

Ouvrez le notebook Colab et examinez la section finale "Plot the predictions along with to the test data", en la comparant avec l’exemple TensorFlow Lite lié. Exécutez le notebook jusqu’à l’entraînement et révisez le graphique afin qu’il représente les données de test et les prédictions de manière pertinente, sans l’avertissement de dépréciation Matplotlib signalé.

Rédigé par le modèle d'indexation à partir du texte de l'issue.