refactor: snake_case primary, camelCase aliases for spec-faithful methods

[chad-loder]

Summary

Promotes PEP-8 snake_case to the canonical spelling on the two methods/properties that previously diverged from PEP-8 to match the WHATWG IDL literally, while keeping the camelCase forms as straight aliases so verbatim-from-spec code still works.

Canonical (new)	Alias (kept)
URLPattern.compare_component(...)	URLPattern.compareComponent(...)
pat.has_regexp_groups	pat.hasRegExpGroups

Both spellings dispatch to the same descriptor — is-identity holds, there's no parallel code path.

Why this shape

In Python wrappers of non-Python APIs, snake_case is almost always primary and camelCase doesn't exist at all — playwright-python uses wait_for_selector not waitForSelector, boto3 uses create_instance, aiohttp uses add_route. The exception is GUI bindings (PyQt, PySide, Tkinter) where the C++/Tcl framework is exposed verbatim. URL-pattern matching is a web-spec wrapper, not a GUI binding, so the ecosystem convention is snake-primary.

But the project has an explicit "literal-text spec portability" value — code that round-trips through MDN / Deno / Bun / Cloudflare-Workers samples should read identically. Keeping compareComponent / hasRegExpGroups as aliases preserves that without inflicting camelCase on PEP-8-strict Python codebases.

How the aliases work

Class-level assignments to the same descriptor:

@staticmethod
def compare_component(component, left, right) -> int: ...

compareComponent = compare_component  # noqa: N815

@property
def has_regexp_groups(self) -> bool: ...

hasRegExpGroups = has_regexp_groups  # noqa: N815

A new test, test_camelcase_aliases_resolve_to_same_callable_and_property, pins the identity contract so a future refactor can't silently re-implement the camel name as a duplicate method.

What changed

• src/yarlpattern/_pattern.py — primary rename + alias declarations. Old # noqa: N802 on the camel def is gone; the new alias lines carry # noqa: N815.
• tests/test_pattern.py, tests/test_wpt_compare.py, scripts/generate_compliance_report.py — switched to the canonical spelling. One new alias-identity test.
• docs/examples/*.md — the four examples that demonstrate specificity ordering use compare_component in their snippets. Readers meet the Pythonic spelling first.
• README.md — one sentence noting the alias.
• SPEC_DEVIATIONS.md — the "Method-name capitalisation" entry rewritten to describe the dual-spelling policy instead of the old "we keep camelCase" stance. Stable-API table row labels show snake (alias camel).
• docs/wpt-compliance.md — regenerated.

Backward compatibility

No breaking change. Every prior usage of URLPattern.compareComponent(...) or pat.hasRegExpGroups continues to work identically.

Test plan

• uv run pytest -q — 951 passed, 8 skipped (was 950 + 1 new alias-identity test)
• just lint — all tools green (ruff, mypy, pyright, ty, semgrep, shellcheck, rumdl, codespell, interrogate, validate-pyproject)
• just docs — strict-mode build green (no broken links, mkdocstrings auto-extracts both spellings)
• just compliance-report — regenerates as 469 cases, 0 failing
• Signed commit (ED25519)