Docs: Fix .html search links and button rendering in dark mode

[hi-ogawa]

(Created by Copilot)

This issue documents two additional points noticed in #9240 beyond the fixed broken link:

1. Links in search have .html suffixes: Links appearing in documentation search results use a .html file extension. This may be unnecessary or inconsistent with expected URLs. Investigate and update documentation build or search config as needed to ensure link consistency and clean URLs.

2. Buttons do not render correctly in dark mode: UI buttons (as visible in search/documentation, according to the screenshot in the referenced PR) are not readable or have styling issues with dark mode enabled. Review and update the documentation site's CSS to correct button rendering in dark mode.

Reference screenshot from PR:

[sheremet-va]

1. The links are correct
2. Is it about the keyboard buttons for easy navigation? They don't seem to be visible

[hi-ogawa]

This is the one on vite.dev

Not sure, but I suppose these are upstream issues. I just wanted to test it out copilot's /create-issue command.

[userquin]

Note: vite using algolia while vitest using local vp seach. The links should be lower case in both cases.

[sheremet-va]

Note: vite using algolia while vitest using local vp seach. The links should be lower case in both cases.

I don't think the issue here is with the search, it's that these buttons are invisible in Vitest:

[sheremet-va]

I think this is probably related to the <kbd> styles I changed some time ago since they are global:

vitest/docs/.vitepress/style/main.css

Line 207 in 60642b3

kbd {

[userquin]

Then we should check the styles and change the color on dark theme, I will check pwa docs (we're using also local search).