fix(highlighter): support custom languages

closed #3067

Author: farnabaz

src/utils/content/index.ts

@@ -4,6 +4,7 @@ import { hash } from 'ohash'
 import type { Highlighter, MdcConfig, ModuleOptions as MDCModuleOptions } from '@nuxtjs/mdc'
 import type { Nuxt } from '@nuxt/schema'
 import { resolveAlias } from '@nuxt/kit'
+import type { LanguageRegistration } from 'shiki'
 import { defu } from 'defu'
 import { createOnigurumaEngine } from 'shiki/engine/oniguruma'
 import { visit } from 'unist-util-visit'
@@ -52,8 +53,8 @@ async function _getHighlightPlugin(options: HighlighterOptions) {
         typeof theme === 'string' ? (await import(`shiki/themes/${theme}.mjs`).then(m => m.default || m)) : theme,
       ]))
     const bundledLangs = await Promise.all(langs.map(async lang => [
-      lang,
-      await import(`@shikijs/langs/${lang}`).then(m => m.default || m),
+      typeof lang === 'string' ? lang : (lang as unknown as LanguageRegistration).name,
+      typeof lang === 'string' ? await import(`@shikijs/langs/${lang}`).then(m => m.default || m) : lang,
     ]))
 
     const highlighter = createShikiHighlighter({