[SPARK-55153][SS][PYTHON][DOC] Add documentation for TwsTester

[fedimser]

What changes were proposed in this pull request?

Add documentation for TwsTester that was added in #53159 and #53491 .

Why are the changes needed?

So users know about TwsTester and can learn from examples how to use it.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Built the docs, screenshots below.

Screenshots for Scala examples:

Was this patch authored or co-authored using generative AI tooling?

Generated-by: claude-4.5-opus-high (only used for proofreading).

[github-actions]

JIRA Issue Information

=== New Feature SPARK-55153 ===
Summary: Add documentation for TwsTester
Assignee: None
Status: Open
Affected: ["4.2"]

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[HeartSaVioR]

@fedimser Would you mind filing a separate ticket for this? We want to bind a PR per ticket unless the PR is really minor. Thanks!

[fedimser]

@fedimser Would you mind filing a separate ticket for this? We want to bind a PR per ticket unless the PR is really minor. Thanks!

Created SPARK-55153.

[HeartSaVioR]

docs directory has a guide to install the library for building website - could you please build the page, and take the part of screenshot for the page so that we ensure the change is rendered properly? You can attach that screenshot into the section of "How was this patch tested?"

Otherwise it looks good to me - I admit I haven't looked at the code line by line since it looks like they were included in Scala/Python PR and I assume you copied properly.

[fedimser]

@HeartSaVioR, I added screenshots.
As for code, it's not exactly copied from tests, I did some small adjustments. But then I copy-pasted these snippets back into test and checked that the tests pass.

[HeartSaVioR]

+1 pending CI

I'll merge this "after" merging the PR #53758