fbeta_score does not accept beta=0. In this case I agree that we could use precision_score which is the same, but is there a reason why this fbeta_score(... beta=0) would be forbidden ? If not I'd be happy to provide a PR. These are the lines that I would delete (plus I would provide a test):

What is more, this case is even mentioned in the documentation ("beta -> 0 considers only precision, beta -> inf only recall)"), so we would reasonably expect it to work ? https://scikit-learn.org/stable/modules/generated/sklearn.metrics.fbeta_score.html