Add wait_closed to the threading implementation.

[aaugustin]

No description provided.

[Copilot]

Pull request overview

Adds wait_closed() to synchronous connections, aligning lifecycle waiting with the asynchronous implementations.

Changes:

• Adds timeout-aware synchronous connection closure waiting.
• Adds coverage for blocking, successful, and timed-out waits.
• Documents the API and updates related test naming.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/websockets/sync/connection.py	Implements wait_closed().
tests/sync/test_connection.py	Tests closure-wait behavior.
tests/asyncio/test_connection.py	Clarifies waiter naming.
tests/trio/test_connection.py	Clarifies waiter naming.
docs/reference/sync/connection.rst	Lists the new base API.
docs/reference/sync/client.rst	Lists the inherited client API.
docs/reference/sync/server.rst	Lists the inherited server API.
docs/project/changelog.rst	Records the feature.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.