chore: code review cleanup + bump v0.8.4

- Remove _get_client_for_output() compat shim (replaced by direct _get_client calls)
- Remove unused inspect import
- Fix redundant branch in constants.get_accept_language()
- Add TWITTER_BROWSER docs to README (en + zh)
- Update all test monkeypatch signatures
- Bump version to 0.8.4

twitter_cli/constants.py

@@ -76,8 +76,6 @@ def get_accept_language():
     # type: () -> str
     tag = _get_locale_tag()
     language = tag.split("-", 1)[0] or "en"
-    if tag == language:
-        return "%s,%s;q=0.9,en;q=0.8" % (tag, language)
     return "%s,%s;q=0.9,en;q=0.8" % (tag, language)