Add JSON schema based auto-completion support

[forgedhallpass]

A really nice addition would be to add support for JSON schema based auto-completion.
This could potentially enable out-of-the-box auto-completion for hundreds of languages, DSLs, config files etc.

Central collection of such schemas can be found at https://www.schemastore.org/json

Some examples of such support can be found in multiple IDEs and editors:

• https://json-schema.org/implementations.html#editors

p.s. I would mostly be interested in using it for YAML files