Consider recommending types-lxml instead of lxml-stubs in import-untyped hint

Bug Report

The import-untyped hint for lxml recommends installing lxml-stubs. The lxml-stubs README seems to recommend the types-lxml fork instead, though:

This repository contains external type annotations (see PEP 484) for the lxml package.
NOTE: It was superceded by the more complete and externally maintained types-lxml fork.

It seems better to recommend types-lxml to users, but it might be more risky for use with --install-types because it is a third-party package.

To Reproduce

import lxml

Actual Behavior

a.py:1: error: Library stubs not installed for "lxml"  [import-untyped]
a.py:1: note: Hint: "python3 -m pip install lxml-stubs"
a.py:1: note: (or run "mypy --install-types" to install all missing stub packages)
a.py:1: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports

Your Environment

• Mypy version used: 1.18.2 and 45aa599
• Mypy command-line flags: N/A
• Mypy configuration options from mypy.ini (and other config files): N/A
• Python version used: 3.13.7

Start by locating the implementation and tests for the import-untyped hint and its recommended stub-package mapping. Reproduce the lxml example, compare the implications of recommending types-lxml versus lxml-stubs, and update the behavior and tests once the package choice is decided.