No language registration for CSS

[fwqaaq]

Describe the bug

If the css logo of my css code block is uppercase (CSS) like the following

```CSS
p{}
```

• When building it produces an error like this:[vitepress] No language registration for CSS

Reproduction

pnpm build-->cause an error,
pnpm dev-->and the preview also creates problems

Expected behavior

Case insensitive on code block identifiers

System Info

[vite] Internal server error: No language registration for CSS
  Plugin: vitepress
  File: E:/Project/CSS/blog-css/docs/css布局/grid.md
      at getGrammar (E:\Project\CSS\blog-css\node_modules\.pnpm\s[email protected]\node_modules\shiki\dist\index.js:2175:19)
      at codeToThemedTokens (E:\Project\CSS\blog-css\node_modules\.pnpm\s[email protected]\node_modules\shiki\dist\index.js:2184:30)
      at Object.codeToHtml (E:\Project\CSS\blog-css\node_modules\.pnpm\s[email protected]\node_modules\shiki\dist\index.js:2201:24)
      at Object.highlight (file:///E:/Project/CSS/blog-css/node_modules/.pnpm/[email protected]/node_modules/vitepress/dist/node/serve-e8d58be3.js:31999:26)    
      at default_rules.fence (file:///E:/Project/CSS/blog-css/node_modules/.pnpm/[email protected]/node_modules/vitepress/dist/node/serve-e8d58be3.js:25746:27) 
      at md.renderer.rules.fence (file:///E:/Project/CSS/blog-css/node_modules/.pnpm/[email protected]/node_modules/vitepress/dist/node/serve-e8d58be3.js:32339:16)
      at md.renderer.rules.fence (file:///E:/Project/CSS/blog-css/node_modules/.pnpm/[email protected]/node_modules/vitepress/dist/node/serve-e8d58be3.js:32828:21)
      at Object.md.renderer.rules.fence (file:///E:/Project/CSS/blog-css/node_modules/.pnpm/[email protected]/node_modules/vitepress/dist/node/serve-e8d58be3.js:32803:12)
      at Renderer$1.render (file:///E:/Project/CSS/blog-css/node_modules/.pnpm/[email protected]/node_modules/vitepress/dist/node/serve-e8d58be3.js:26025:38)   
      at MarkdownIt.render (file:///E:/Project/CSS/blog-css/node_modules/.pnpm/[email protected]/node_modules/vitepress/dist/node/serve-e8d58be3.js:31950:24)

Additional context

No response

Validations

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• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

[brc-dd]

It should be in lowercase always.

[fwqaaq]

It should be in lowercase always.

😯，but compatible uppercase will have better support

[brc-dd]

But it will be non-standard too. Most of the tools don't support this. Say for example if you write CSS there instead of css and format your code with Prettier, then it won't apply CSS formatting to the code block's contents.

[fwqaaq]

Well, then I will provide support myself. Vuepress has no problem in this regard though