chore: adjust base on comments

Author: l-qing

docs/container-contract.md

@@ -46,9 +46,11 @@ the container will execute using the default `entrypoint` defined in the image.
 spec:
   steps:
     - image: gcr.io/cloud-builders/gcloud
-      # No command specified, so the default entrypoint from the image will be used
+      # No command specified, so the default entrypoint `/builder/notice.sh` from the image will be used
+      # command: ["/builder/notice.sh"]
     - image: gcr.io/cloud-builders/docker
-      # No command specified, so the default entrypoint from the image will be used
+      # No command specified, so the default entrypoint `/usr/bin/docker` from the image will be used
+      # command: ["/usr/bin/docker"]
 ```
 
 However, if you specify a custom `command` value, the controller uses that value instead: