fix highlighting for etl pages

[proddata]

Summary of the changes / Why this is an improvement

Let's fix this in the most straightforward way.

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kudos to @amotl for finding this

Note

"So let's find the closest header in the document and try with that one."
https://github.com/petermd/sphinx_rtd_theme/blob/0.2.4/js/theme.js#L93-L123

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Checklist

• Link to issue this PR refers to (if applicable): Highlighting of "current" item in primary navigation is wrong crate-docs-theme#499
• CLA is signed

[amotl]

If that improves something, I am happy. Thanks. Feels like hacking on the edge of Sphinx, but c'est la vie?

[proddata]

Feels like hacking on the edge of Sphinx, but c'est la vie?

Reading through the js snippet and sphinx docs you linked, I think that is exactly the way it is supposed to work 🙈

"If it is stupid but it works, it isn't stupid."