Dagu YAML intellisense

Found this on a quick web search:
https://joshuaavalon.io/intellisense-json-yaml-vs-code
https://dev.to/brpaz/how-to-create-your-own-auto-completion-for-json-and-yaml-files-on-vs-code-with-the-help-of-json-schema-k1i

And hopefully in the future we could bring this to the code editor in the web UI