feat: add rehype-slug for TableOfContents heading IDs

app/posts/[slug]/page.tsx

@@ -5,6 +5,7 @@ import remarkMath from 'remark-math'
 import remarkGfm from 'remark-gfm'
 import rehypePrettyCode from 'rehype-pretty-code'
 import rehypeKatex from 'rehype-katex'
+import rehypeSlug from 'rehype-slug'
 import { getPosts, getPost, getReadingTime } from '@/lib/posts'
 import { TableOfContents } from '@/components/blog/TableOfContents'
 import { ScrollToTop } from '@/components/ui/ScrollToTop'
@@ -55,6 +56,7 @@ export default async function PostPage({ params }: { params: Promise<{ slug: str
                   mdxOptions: {
                     remarkPlugins: [remarkMath, remarkGfm],
                     rehypePlugins: [
+                      rehypeSlug,
                       [rehypePrettyCode, { theme: 'github-dark' }],
                       rehypeKatex,
                     ],