Update README.md

Author: jmau111

README.md

@@ -57,7 +57,7 @@ Open `./gatsby-config.ts` and modify:
   },
 ```
 
-I use pathPrefix because I host the demo in a subfolder, but **you don't have to use this parameter if your production URL is a root URL**. 
+I use `pathPrefix` because I host the demo in a subfolder, but **you don't have to use this parameter if your production URL is a root URL**. 
 
 For more advanced users, there's the dotenv module, but it's not configured yet.