Support multisite search on pagefind

[XREvo]

Description

• Closes Support multisite search on pagefind #2856
• It add more configuration option to pagefind, by allowing mergeIndex
• No visual changes had been made with this update.

This had been tested locally with 2 instances :

• one on port 3000 and the other on port 3001
• with this configuration

export default defineConfig({
	... ,
	integrations: [
		starlight({
			...,
			pagefind: {
				indexWeight: 2.0,
				mergeIndex: [{
					bundlePath: 'http://localhost:3001/pagefind/',
					indexWeight: 0.5,
				}]
			},
		}),
	],
});

• and network panel show that both sites where queried for search
  

What's next

• Completing the doc to let users known that they can use it (i'll do it in the the next days)

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Latest commit: 97a4f6f

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Name	Type
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[delucis]

Thank you for the PR @XREvo! I’ve left a few comments.

One additional note: could you remove the changes to the non-English docs? In general we only change the English docs in implementation PRs and then allow our translators to update their individual languages to ensure they can fully update things correctly for their linguistic context.

[XREvo]

I've reverted my modification of translations with 10d9967

[XREvo]

I let you resolve the conversations after review and i'm waiting for your feedback about the mergeFilter property.
And thanks for the review 🙏

[delucis]

Thanks for your patience on this one @XREvo! I think it looks good, and the mergeFilter schema seems correct to me.

I left a bunch of comments, but please don’t feel overwhelmed — they’re all tiny details to improve the documentation/comments 😁

I’m also happy to handle applying these if you prefer.

[XREvo]

Thanks @delucis for this careful review
I've added all your changes, they were legit to my eyes.

[delucis]

Thanks again for the PR @XREvo! Will get this published as part of our next minor release 🙌