docs: rewrite test_to_doc_links how-to for C++, Rust, and Python

[a-zw]

See https://eclipse-score.github.io/docs-as-code/pr-549/how-to/test_to_doc_links.html

[github-actions]

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bazel run --lockfile_mode=error //src:license-check

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[License Check Output]
Extracting Bazel installation...
Starting local Bazel server (8.4.2) and connecting to it...
INFO: Invocation ID: b85a0eba-86aa-429b-b425-a74f75890e8c
Computing main repo mapping: 
Loading: 
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WARNING: Target pattern parsing failed.
ERROR: Skipping '//src:license-check': no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
ERROR: no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
INFO: Elapsed time: 4.852s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target

[github-actions]

The created documentation from the pull request is available at: docu-html

[AlexanderLanin]

AI-assisted review (Claude):

Severity breakdown: Critical: 0, Important: 1, Suggestions: 1

Nice rewrite — the structure is much clearer and the language-specific guidance with cross-references to requirements is a solid improvement over the old Python-only example.

One accuracy issue with the Description property claim (see inline comment) and one minor discoverability note about a dropped cross-reference to dashboards_and_quality_gates. The old doc had a "Related" section linking there — might be worth keeping as a brief "See also" since it covers end-to-end dashboard and CI threshold setup, which is a natural next step after setting up test links.

The two external need references (gd_guidl__verification_specification, gd_temp__verification_specification) appear to resolve correctly in the PR preview build, so those look fine.