i18n(fr): fix code example in configuration-reference.mdx (#9193)

See #9188

Co-authored-by: Yan <61414485+yanthomasdev@users.noreply.github.com>

src/content/docs/fr/reference/configuration-reference.mdx

@@ -1734,7 +1734,7 @@ import { getEntry, render } from 'astro:content';
 
 const post = await getEntry('blog', Astro.params.slug);
 
-const { Content, headings } = await render(entry);
+const { Content, headings } = await render(post);
 ---
 
 <Content />