theme: Swap sidebar order

[bep]

A quick take on this from me.

So, I agree in the situations where the toc is relatively short, but I don't think it's a great idea when the toc covers most of the screen.

See #2936

[jmooring]

Thanks. I waffled on this one for the reason stated above, and my opinion may change again when we have a section menu. For now I vote to merge this.

[bep]

Yea, probably right -- there's some non-trivial overflow/scroll issues that needs to be fixed before merging this, though.

[jmooring]

@bep I'd like to revisit this. I asked Gemini and it had this to say:

It's generally recommended that "On This Page" comes before "In This Section" in a webpage's sidebar.

Here's why:

• Immediate Relevance: "On This Page" provides a table of contents for the current page the user is viewing. This information is immediately relevant and helps the user quickly navigate within the content they are actively consuming.
• Hierarchical Understanding: "In This Section" typically refers to other pages or sub-sections within a larger, broader category of content. While important for broader navigation, it's a step removed from the immediate content. Users usually want to understand the current page's structure before exploring related pages.
• User Flow: Users often land on a specific page with a particular goal in mind. "On This Page" helps them achieve that goal more efficiently by pinpointing relevant sections. Once they've explored the current page, they might then look to "In This Section" for further related information.

Think of it like reading a book: you'd look at the table of contents for the current chapter (On This Page) before looking at the overall table of contents for the entire book (In This Section).

The above aligns with my thoughts and opinions.

And when I say "I'd like to revisit this" what I actually mean is, "Would you please have another look at this PR and make the necessary changes?"