Use SSL context for "wss" scheme

[MtkN1]

Summary

This pull request addresses an issue where connecting to a WebSocket server using the "wss" scheme with TLS connection is not possible. (I have not created a discussion, but since it is a small bug fix, I have created a pull request 🙏)

The problem lies in the condition that enables the SSL context, which currently only allows the "https" scheme. This pull request adds the "wss" scheme to the conditions for enabling the SSL context.

Real-world reproduction code: ("echo.websocket.events" is a publicly available WebSocket echo server)

import httpcore

# no secure (success)
with httpcore.ConnectionPool() as pool:
    with pool.stream("GET", "ws://echo.websocket.events") as response:
        print("no secure", response)

print("-" * 80)

# secure (failed)
with httpcore.ConnectionPool() as pool:
    with pool.stream("GET", "wss://echo.websocket.events") as response:
        print("secure", response)

Output:

no secure <Response [200]>
--------------------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/tmp.qSsd6WTpkd.py", line 12, in <module>
    with pool.stream("GET", "wss://echo.websocket.events") as response:
  File "/home/codespace/.python/current/lib/python3.10/contextlib.py", line 135, in __enter__
    return next(self.gen)
  File "/workspaces/httpcore/httpcore/_sync/interfaces.py", line 75, in stream
    response = self.handle_request(request)
  File "/workspaces/httpcore/httpcore/_sync/connection_pool.py", line 268, in handle_request
    raise exc
  File "/workspaces/httpcore/httpcore/_sync/connection_pool.py", line 251, in handle_request
    response = connection.handle_request(request)
  File "/workspaces/httpcore/httpcore/_sync/connection.py", line 103, in handle_request
    return self._connection.handle_request(request)
  File "/workspaces/httpcore/httpcore/_sync/http11.py", line 132, in handle_request
    raise exc
  File "/workspaces/httpcore/httpcore/_sync/http11.py", line 110, in handle_request
    ) = self._receive_response_headers(**kwargs)
  File "/workspaces/httpcore/httpcore/_sync/http11.py", line 175, in _receive_response_headers
    event = self._receive_event(timeout=timeout)
  File "/workspaces/httpcore/httpcore/_sync/http11.py", line 225, in _receive_event
    raise RemoteProtocolError(msg)
httpcore.RemoteProtocolError: Server disconnected without sending a response.

Tests

1. In the first commit, I modified existing tests to fail. I added a Trace to the test to track the condition for enabling the SSL context. The test fails because the Trace "connection.start_tls.{started,complete}" is missing due to the absence of the "wss" scheme in the conditions for enabling the SSL context.
2. In the second commit, I added the "wss" scheme to the conditions for enabling the SSL context. This ensures that the initially failing test now succeeds.

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.

[tomchristie]

😅 Reasonable. Neat test case.
Let's have a CHANGELOG.md entry for it, and we can get this in.

[MtkN1]

Thank you for the review!
I have updated a CHANGELOG.md.

[tomchristie]

Sure, thanks.