Migrate JsonRPCServer.start_tcp and JsonRPCServer.start_ws to high level asyncio APIs

[alcarney]

This PR completes the migration of the server-side of pygls to the higher level asyncio APIs
Closes #334

start_tcp

• Since asyncio.start_server gives us a reader, writer pair it's enough to reuse the run_async method from the pygls.io_ module.

start_ws

• This moves the WebSocketTransportAdapter into pygls.io_ and a new run_websocket function, allowing the websocket main loop to be shared between client and server code
• This PR also takes the opportunity to migrate to the new websockets.asyncio API

It's also worth noting that the test suite now includes the values of --lsp-runtime and --lsp-transport in the header pytest prints at the start of a test run

$ pytest
=========================================== test session starts ===========================================
platform linux -- Python 3.13.0, pytest-8.3.3, pluggy-1.5.0
rootdir: /var/home/alex/Projects/openlawlibrary/pygls/main
configfile: pyproject.toml
plugins: cov-5.0.0, asyncio-0.24.0
asyncio: mode=Mode.AUTO, default_loop_scope=None
pygls: runtime='cpython', transport='stdio'         <-- NEW!
collected 222 items                                                                                                

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• Title summarizes what is changing
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• Tests have been included and/or updated, as appropriate
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• Standalone docs have been updated accordingly

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[tombh]

THIS PR <-- GREAT!

[alcarney]

Thanks!