Check if X_intact contains missing data for imputation models, check and list mismatched hyperparameters in the tuning mode

[WenjieDu]

What does this PR do?

1. fixing For imputation models, X_intact in the val set containing missing data will cause NaN loss #232;
2. fixing Check if tuning hyperparameters match with the model's arguments in the tuning mode #233;
3. updating docs;

Before submitting

• This PR is made to fix a typo or improve the docs (you can dismiss the other checks if this is the case).
• Was this discussed/approved via a GitHub issue? Please add a link to it if that's the case.
• I have commented my code, particularly in hard-to-understand areas.
• I have written necessary tests and already run them locally.