Fix docstring Args entries that name a parameter the function does not take - #22733

Twenty-two Args: entries name a parameter the function does not take. Docstrings only — no signature, no behaviour, no test touched.

Twelve are renames where the docstring kept the old name:

send_worker_heartbeat also referred to return_id a second time inside its own description, so that went too.

The other ten document something that is not an argument:

• PrefectEventSubscriber.__init__ documents api_key, which the constructor does not take — it reads the auth string from settings.
• Flow.retry documents return_state; it takes only flow_run.
• Task.serve and Task.aserve document task_runner; both take no arguments at all, so the whole Args: block went.
• AsyncPostgresConfiguration.engine and AioSqliteConfiguration.engine each document connection_url, echo and timeout. All three are attributes — the entries even say "Defaults to self.connection_url" — and engine() takes only self.

Every entry was opened and read against its signature. ruff check and ruff format --check pass on all twelve files with the pinned ruff==0.15.19 from .pre-commit-config.yaml.