Update configuration.mdx

Author: noam-honig

docs/tutorialkit.dev/src/content/docs/reference/configuration.mdx

@@ -243,11 +243,11 @@ Example value:
 previews:
   - 3000 # Preview is on :3000/
   - "3001/docs" # Preview is on :3001/docs/
-  - false # Do not show preview panel
   - [3002, "Dev Server"] # Preview is on :3002/. Displayed title is "Dev Server".
   - [3003, "Dev Server", "/docs"] # Preview is on :3003/docs/. Displayed title is "Dev Server".
   - { port: 3004, title: "Dev Server" } # Preview is on :3004/. Displayed title is "Dev Server".
   - { port: 3005, title: "Dev Server", pathname: "/docs" } # Preview is on :3005/docs/. Displayed title is "Dev Server".
+previews: false # Do not show preview panel
 ```
 
 ##### `mainCommand`