fix vite and solid in dev

Inclusion of @astrojs/markdown-remark caused errors that cause solid
and vite to fail to load in dev. It's stripped in build.

src/config/io/markdown.ts

@@ -96,7 +96,6 @@ export const markdownConfig: AstroMarkdownOptions = {
   remarkPlugins: [[remarkAlert, { legacyTitle: true }]],
   rehypePlugins: [
     // FIXME: incompatible types between unified/Plugin and Astro/RehypePlugin
-    // @ts-expect-error
     [sectionize as RehypePlugin, { idPropertyName: "id" }],
     rehypeRewriteTypelinks,
   ],