Convert every remaining `to_trio`/`from_trio` fn-sig style
to the new unified `chan: LinkedTaskChannel` iface added in
prior commit (c46e9ee8).
Deats,
- `to_trio.send_nowait(val)` (1st call) -> `chan.started_nowait(val)`
- `to_trio.send_nowait(val)` (subsequent) -> `chan.send_nowait(val)`
- `await from_trio.get()` -> `await chan.get()`
Converted fns,
- `sleep_and_err()`, `push_from_aio_task()` in
`tests/test_infected_asyncio.py`
- `sync_and_err()` in `tests/test_root_infect_asyncio.py`
- `aio_streamer()` in
`tests/test_child_manages_service_nursery.py`
- `aio_echo_server()` in
`examples/infected_asyncio_echo_server.py`
- `bp_then_error()` in `examples/debugging/asyncio_bp.py`
Also,
- drop stale comments referencing old param names.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code