[Workflows] explain workflow_id and task_name

[enori]

I'm a beginner for Ray.
I am studying Ray with the nice documents.

Why are these changes needed?

In the Ray Workflow section,
I found it difficult to understand what happens if the workflow_id or task_name is not given.

Perhaps the sample code writes the output result on the right side of the equation so that the equation is True.
I expected that and ran it, but got a little confused because I got different results in the Retrieving results section.
Also, I think there is a function that automatically adds a suffix with a counter _n to the task_name when there are tasks with the same name, but I found it difficult to understand the relationship between the number of _n and each task.

Related issue number

Open: #25715

Checks

• 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 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 :(

Since this PR does not affect the functionality of Ray itself, no specific testing has been done.

[suquark]

Thank you for fixing the workflow docs!

We are also undergoing some major refactoring and will polish the workflow docs recently (e.g., the _n suffix when the name duplicates).