Provide default object as completion snippet

[evidolob]

Fix: redhat-developer/vscode-yaml#200

[JPinkney]

I've just tried testing this and it looks like I'm getting unexpected results.

Attempting to autocomplete:

env: 

in VSCode gives

env: 	KEY: VALUE

which is invalid YAML. I think it needs to do:

env:
  KEY: VALUE

[evidolob]

@JPinkney Yes, you are right

[JPinkney]

I've tested with:

{
    "type": "object",
    "properties": {
        "env": {
            "type": "object",
            "default": {
                "KEY": "VALUE",
                "KEY2": {
                    "TEST": "TEST2"
                },
                "KEY3": ["Test", "Test2"]
            }
        }
    }
}

and it looks like we get:

env: 
  KEY: VALUE
  KEY2: [object Object]
  KEY3: Test,Test2

I wonder if it makes sense to continously check every child value as well. I've just tried with json language server and it seems to work correctly:

{
    "env": {
        "KEY": "VALUE",
        "KEY2": {
            "TEST": "TEST2"
        },
        "KEY3": [
            "Test",
            "Test2"
        ]
    }
}

[evidolob]

@JPinkney I done:

[JPinkney]

Works great!