Use proper header in troubleshooting page (#12651)

Co-authored-by: Armand Philippot <[email protected]>

Author: fvictorio

src/content/docs/en/guides/troubleshooting.mdx

@@ -186,7 +186,7 @@ You may notice an imported component's `<style>` tag included in your HTML sourc
 
 Astro's build process works on the module graph: once a component is included in the template, its `<style>` tag is processed, optimized, and bundled, whether it appears in the final output or not.
 
-## Escaping special characters in Markdown
+### Escaping special characters in Markdown
 
 Certain characters have a special meaning in Markdown. You may need to use a different syntax if you want to display them. To do this, you can use [HTML entities](https://developer.mozilla.org/en-US/docs/Glossary/Entity) for these characters instead.