Wrong dev containers command for devcontainer.secure.json

https://github.com/openai/codex/blob/e7bffc5a20e92cbc64d6c16a1b257d0b2e4cd5df/.devcontainer/README.md?plain=1#L25-L31

These steps in the documentation don't work:

1. Dev Containers only accepts a config file named devcontainer.json or .devcontainer.json
2. Open Folder in Container as the name indicates, lets you choose a folder, not a file.

I'm not sure if these are the instructions pushed to https://developers.openai.com/codex/agent-approvals-security#run-codex-in-dev-containers, since I couldn't find the repo for that site.