Accept trailing dot on simple hostnames with rfc_1034

[assinscreedFC]

Summary

Refs #442.

rfc_1034 is documented as "Allow trailing dot in domain/host name", but it only worked for dotted names (handled by domain()):

>>> import validators
>>> validators.hostname("ie",  rfc_1034=True)   # True
>>> validators.hostname("ie.", rfc_1034=True)   # False  <- inconsistent
>>> validators.hostname("defo.ie.", rfc_1034=True)  # True

A simple, single-label hostname goes through _simple_hostname_regex(), which does not permit a trailing dot, so "ie." failed even with rfc_1034=True, while "ie" passed.

Fix

Strip an optional trailing dot before the simple-hostname check when rfc_1034 is set, so a single-label hostname behaves the same with and without the dot. The trailing dot is still rejected when rfc_1034 is False.

>>> validators.hostname("ie.",  rfc_1034=True)   # now True
>>> validators.hostname("ie.",  rfc_1034=False)  # still False

Scope

This addresses the hostname() inconsistency from #442. I deliberately left domain()'s rejection of bare single-label names (domain("ie") → False with or without a dot) unchanged, since whether a single label counts as a "domain" is a separate policy question — happy to follow up if you'd like it changed too.

Test plan

• Added single-label trailing-dot cases to tests/test_hostname.py (valid with rfc_1034=True, invalid without).
• pytest tests/test_hostname.py tests/test_domain.py — 90 passed.
• ruff check / ruff format --check — clean.
• Note: the full suite has 17 pre-existing, unrelated failures in tests/crypto_addresses/test_eth_address.py (present on a clean checkout, before this change).