Proposal: patch function for editing JSON5 while preserving comments (WIP)

[giacomorebonato]

This branch adds a patch function to the public API.

Its purpose is to allow the editing of a JSON5 object while preserving the comments in the file.
The API works like this.

let json5Text = `
  {
    hello: 'world' // this is a comment
  }
`

json5.patch(
  json5Text,
  {
    hello: 'world',
    my: 'friend'
  }
)

/* returns a string like this 
`
  {
    hello: 'world', // this is a comment
    my: 'friend'
  }
`

*/

Note that the comment is still present in the string. The above example is the most simple I can imagine, but it should work in many other cases that I mean to cover in the tests.

What do you think? Would you be welcoming such an addition @jordanbtucker ?
Happy to ultimate the work if so and I'll close the PR if you believe that it's out of the scope of this library.

Mentioning that:

• this is something that comment-json provides, but without JSON5
• this work comes almost entirely by looking at golden-fleece by Rich Harris
• Options for preserving comments when editing a JSON5 file by script #177