fix the get_event_loop() depricatin issue in asyncio.rst docs/tutorials

[matthewwilson-gh]

PR description:

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Fix get_event_loop() deprecation in asyncio tutorial

Replaces the deprecated asyncio.get_event_loop() + run_until_complete() pattern in docs/tutorials/asyncio.rst with asyncio.run().

Before: The tutorial used get_event_loop() (deprecated in Python 3.10 when no event loop is set) and manually ran the coroutine with loop.run_until_complete().

After: Uses asyncio.run() to run the gathered coroutines. This is the recommended way to run async code from sync code (Python 3.7+) and handles loop creation and cleanup.

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