Describe the issue linked to the documentation

References #29775

Issue

The text in the MAPE formula is incorrect.

The MAPE formula here represents a relative error and outputs a value in the 
    range [0, 1]. It is not a percentage in the range [0, 100] and a value of 100 
    does not mean 100% but 1e2. The motivation for the MAPE formula here to be in
    the range [0, 1] is to be consistent with other error metrics in scikit-learn 
    such as `accuracy_score`.

Discussion for resolution

1. update the upper range
2. provide examples

• MAPE is not in the range [0, 1], it can be arbitrarily large, right? I have to say I don't really know how to word this to make it clearer that a percentage is not returned despite the name.

• Indeed you can make an error of 200%. We need to reformulate and drop the notion of upper bound.

• Maybe give an example where the error is 1 (or 100%) in the user guide to clarify that the returned value is 1 and not 100?

Suggest a potential alternative/fix

No response