Update toJSON example in JSDOCs

[asturur]

toJSON examples are still referencing additional properties and should be updated to reflect the recent change, they don't support additional properties anymore indeed.

[SandeepUrankar]

Hey, could you please tell me more about it?

[asturur]

we had toObject as an alias of toJSON.
By javascript specs toJSON
https://tc39.es/ecma262/multipage/structured-data.html#sec-json.stringify
is called with key as first argument for nested objects.

Our toObject function accepts a parameter that is an array of properties, while toJSON can't don't that because the first argument is defined by javascript specs.

our examples in the codebase treated toObject as toJson, so you will find in the codebase a string like this:

   * var json = canvas.toJSON(['lockMovementX', 'lockMovementY', 'lockRotation', 'lockScalingX', 'lockScalingY']);

where this is wrong.

it can either be:

   * var json = canvas.toObject(['lockMovementX', 'lockMovementY', 'lockRotation', 'lockScalingX', 'lockScalingY']);

or

   * var json = canvas.toJSON();

So that wrong toJSON example needs to be deleted and if other are found need to be deleted as well.