Rename class MahalanobisDistance to reflect it is a Mahalanobis-like distance

[luisheb]

Description:

The class currently named MahalanobisDistance implements a distance that approximates the Mahalanobis concept for functional data, but it does not strictly match the classical Mahalanobis distance. To avoid misleading users and to align more closely with the terminology used in the literature, the class should be renamed.

This type of distance is commonly referred to as a Mahalanobis-type distance in functional data analysis. However, to prevent confusion with programming data types, we suggest using the name MahalanobisLikeDistance.

A relevant reference that uses this terminology is:

Martino, A., Ghiglietti, A., Ieva, F. et al. A k-means procedure based on a Mahalanobis type distance for clustering multivariate functional data. Stat Methods Appl 28, 301–322 (2019). https://doi.org/10.1007/s10260-018-00446-6

Suggested change:

Rename the class from MahalanobisDistance to MahalanobisLikeDistance