Extension is activated on XML, YAML, JSON files

[IronGeek]

The extension manifest (package.json) defines the activationEvents as:

...
"activationEvents": [
    "onLanguage:xml",
    "onLanguage:yaml",
    "onLanguage:json",
    "onLanguage:json-tmlanguage",
    "onLanguage:yaml-tmlanguage",
    "onLanguage:tmlanguage"
  ],
...

I'm aware that tmLanguage file is essentially an XML file, and that json-tmLanguage and yaml-tmLanguage file is a JSON, and YAML file respectively. But this is not vice versa; not all XML, YAML, and or JSON file is a *tmLanguage file.

I think the extension should not be activated for an XML, YAML, or JSON file by default.
If user does need to have an XML, YAML, or JSON file treated as tmLanguage file, he/she can still do so via the Change Language Mode dropdown.