docs: backend integration clarify tags to include in production HTML

[brownan]

Description

While writing my own backend integration, the documentation wasn't clear to me what tags were required in generated HTML. After looking at what the vite build-html plugin does, and what a couple other integrations do, I wanted to update the documentation with what I found. I hope this clarifies how backends should interpret the manifest and what HTML tags they should generate.

Additional context

Some integrations recursively followed imports and included script tags for imported javascript chunks, and some included <link rel="modulepreload"> tags. Is there an official stance from the project on how imported javascript chunks should be included? I consider them optional since the entry point chunk's javascript imports any dependent javascript files anyways, so it'd just be an optimization.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Contributing Guidelines, especially the Pull Request Guidelines.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Update the corresponding documentation if needed.
• Ideally, include relevant tests that fail without this PR but pass with it.

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[brownan]

Thanks for the feedback! I agree, it's still useful to include an example template. I've modified it to fit in with the description more closely. Also I realized that each chunk can have multiple css files, and that both functions can be simplified to a single function which recursively gets the imported chunks. Let me know what you think of this. I feel the two examples and the description flow nicely together now.

[brownan]

@patak-dev if you have a chance, can you take a look at the changes I made? Thanks!

[patak-dev]

Looks great, thanks for working on this!