Swap the deprecated `portal.result()` calls for the modern
`.wait_for_result()` spelling in,
- `a_trynamic_first_scene.py` (x2)
- `actor_spawning_and_causality.py`
- `parallelism/single_func.py`
These 3 are literalinclude'd by the new docs tree so the rendered
code must teach the current api; the `debugging/` set still calls
`.result()` (pexpect pattern-matched tests, left for a follow-up
sweep).
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code