Crypto_Feature_Importance.ipynb, training use future data

## 3.1 Set constants and train/test split

`X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, stratify=y, random_state=69)`

`shuffle=False` should be add.

Open Crypto_Feature_Importance.ipynb and go to section 3.1, “Set constants and train/test split.” Review the train_test_split call shown in the issue, make the requested split behavior change, and rerun the notebook to confirm the training and test data no longer use shuffled future data.

Scritto dal modello di indicizzazione a partire dal testo della issue.