Rely on URL paths when choosing among multiple indices

[mportiz08]

Bug/issue #, if applicable: 142337934

Summary

This updates the logic used to choose between multiple top-level trees of data for the sidebar navigator:

Before, it would pick the first module in the list. (see #916)

Now, it will pick the first node with a path prefix matches the path prefix of the current URL.

This logic should only apply to rare scenarios where multiple trees of index data are included in a single Index JSON file.

Testing

Steps:

1. Verify that there are no regressions with loading sidebar data in common, single-root scenarios.
2. Verify that the data loaded for the index generally matches what would be expected given the current URL in scenarios where there are multiple roots of index data.

Checklist

Make sure you check off the following items. If they cannot be completed, provide a reason.

• Added tests
• Ran npm test, and it succeeded
• Updated documentation if necessary

[mportiz08]

@swift-ci test

[mportiz08]

@swift-ci test

[marinaaisa]

I'm not very happy about relying on window.location but I haven't found a better alternative.

I tried a different approach where I imported the Vue's router into the navigatorData.js file and used currentRoute.fullPath to retrieve the path without the baseUrl prefix.

It wasn't cleaner than using window.location and it had some potentially risky changes in the main.js file so I don't think it's a good alternative.

Let's go with this approach then! Thank you @mportiz08