[2.50 cherry-pick] Actor Typing documentation

[richardliaw]

Why are these changes needed?

follows up from previous type hint improvement PRs to add to mainline docs.

Related issue number

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
• I've added any new APIs to the API Reference. For example, if I added a
  method in Tune, I've added it in doc/source/tune/api/ under the
  corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

---

Why are these changes needed?

Related issue number

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run pre-commit jobs to lint the changes in this PR. (pre-commit setup)
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[gemini-code-assist]

Code Review

Thank you for adding this important documentation on actor typing. The explanations are clear and the example is very helpful for users looking to adopt typed actors. I have one suggestion to make the example even better by making it verifiable.

[gemini-code-assist]

To make this example more complete and verifiable, it's a good practice to include the expected output using a .. testoutput:: block, similar to other examples in this file. This ensures the example code produces the correct result when the documentation is tested.

The output of print(ray.get(obj_ref)) will be 1.

Suggested change

	print(ray.get(obj_ref))
	print(ray.get(obj_ref))
	.. testoutput::
	1