Describe the issue linked to the documentation

Some of the metrices in #2805 were implemented in #7739.

Suggest a potential alternative/fix

It would be nice to add (to) an example the usage of those ranking metrices with the addition of, e.g., kendall's tau and spearman's rho:

from scipy.stats import kendalltau, spearmanr
from sklearn.metrics import make_scorer

kenall_tau_score = make_scorer(kendalltau)
spearman_rho_score = make_scorer(kendalltau)