完善 mdx 文件处理，修复代码高亮问题

src/mdx-components.tsx

@@ -1,7 +1,17 @@
 import type {MDXComponents} from 'mdx/types'
-
-const components: MDXComponents = {}
+import {merge} from './lib/utils'
 
 export function useMDXComponents(): MDXComponents {
-  return components
+  return {
+    wrapper: props => (
+      <article
+        {...props}
+        className={merge(
+          `prose max-w-none`,
+          props.className,
+        )}>
+        {props.children}
+      </article>
+    ),
+  }
 }