Bugfix: 'Array' output with JSON properties that have multiple types

Instead of showing a list of the datatypes for state/open in the documentation, the String 'Array' was output which came from the PHP typecast.

...
"properties": {

    "open": {
        "description": "...",
        "required": true,
        "type": [
            "boolean",
            "null"
        ]
    },
...