Using a json schema in a vscode extension for a file type

[chschrae]

Hi all, I have a yml file extenstion type called 'myYaml' which I would like to use a json schema to enable autocomplete.

I have added the contributes points like follows:

"contributes": {
    "commands": [
      {
        "command": "helloworld.helloWorld",
        "title": "Hello World"
      }
    ],
    "yamlValidation": [
      {
        "fileMatch": "*.myYaml",
        "url": "./myYaml.yaml.schema.json"
      }
    ]
  },

But I still don't get auto completion or association on the file when running the extension. Is there more to associating the file types with an extension?