Patterns: validate Patterns index pages

[Eric-Arellano]

In #1294, each of the 4 patterns pages links out to the rest of the docs app. It provides an alternative organization than the tools-based approach.

We are going to manually maintain both guides/_toc.json and those 4 index pages. There are a few edge cases that would be too complex for us to generate the index files in a clear way. It's best to let humans decide what goes where.

However, we want an automated check to ensure that every page shows up both in the Tools folders & in the Workflow index pages. Likewise, a page should never show up >1 time in the _toc.json or the index pages. The check should not care what TOC section/workflow index the specific page shows up in; we only need to validate that it shows up exactly once in both places.

This code is probably useful for how to parse the index pages:

documentation/scripts/lib/api/TocGrouping.test.ts

Line 80 in 2974d28

async function getIndexModuleGroups(fp: string): Promise<ModuleGroup[]> {

Note that the index pages may have sublists, like * with indentation.

We probably need an allowlist mechanism. Right now, Qiskit Serverless only shows up in the Tools and not Workflow index pages.