diff --git a/src/content/configuration/externals.md b/src/content/configuration/externals.md
index 608fa59a1acf..2d57bf024dc2 100644
--- a/src/content/configuration/externals.md
+++ b/src/content/configuration/externals.md
@@ -96,7 +96,7 @@ will compile to something like:
 const fs = require('fs-extra');
 ```
 
-### [string]
+### `[string]`
 
 ```javascript
 module.exports = {