docs: update MDC support

Author: antfu

guide/animations.md

@@ -342,7 +342,7 @@ Experimental: This is not supported by all browsers. Check the [Browser compatib
 
 You can use the `view-transition-name` CSS property to name view transitions, which creates connections between different page elements and smooth transitions when switching slides.
 
-You can enable [MDC (Markdown Component) Syntax](https://content.nuxtjs.org/guide/writing/mdc) support to conveniently name view-transitions:
+You can enable [MDC (Markdown Component) Syntax](/syntax#mdc-syntax) support to conveniently name view-transitions:
 
 ```md
 ---

guide/syntax.md

@@ -646,11 +646,11 @@ src: ./content.md
 
 > Available since v0.43.0
 
-Slidev has an experimental support for [MDC (Markdown Components) Syntax](https://content.nuxtjs.org/guide/writing/mdc) powered by [`markdown-it-mdc`](https://github.com/antfu/markdown-it-mdc).
+Slidev supports optional [MDC (Markdown Components) Syntax](https://content.nuxtjs.org/guide/writing/mdc) powered by [`markdown-it-mdc`](https://github.com/antfu/markdown-it-mdc).
 
 You can enable it by adding `mdc: true` to the frontmatter of your markdown file.
 
-```md
+```mdc
 ---
 mdc: true
 ---
@@ -664,4 +664,4 @@ The **default** slot
 ::
 ```
 
-Learn more about [the syntax](https://content.nuxtjs.org/guide/writing/mdc).
+Learn more about [the syntax](https://content.nuxt.com/guide/writing/mdc).