Add comma-dangle option

[rtritto]

Add a comma-dangle boolean option.

Example

With:

const data = {
  key1: 'value1'
}

Case 1

Options:

JSON5.stringify(data, null, 2, { commaDangle: false, quote: '\'' })

Output:

{
  key1: 'value1'
}

Case 2 (Current behavior)

Options:

JSON5.stringify(data, null, 2, { commaDangle: true, quote: '\'' })

Output:

{
  key1: 'value1',
}