Comma is inserted after comment when serializing flow map

[WhiteAbeLincoln]

Describe the bug
When serializing a flow mapping, the separating comma is appended to a trailing comment instead of after a value.
This results in an invalid yaml document (despite no changes being made to the document) because of a missing comma between flow map items.

This behavior does not occur with a flow sequence, just a flow map.

To Reproduce

const yaml = require('yaml')
const assert = require('node:assert')

const textBefore =
`test: {
  items: {
    first: { value: true }, # comment
    second: { value: true }
  },
  array: [
    first, # comment
    second
  ]
}`

const textAfter =
`test:
  {
    items:
      {
        first: { value: true } # comment,
        second: { value: true }
      },
    array:
      [
        first, # comment
        second
      ]
  }`

const doc = yaml.parseDocument(textBefore)

const docText = doc.toString()

// no error
assert.equal(docText.trim(), textAfter)

const docAfter = yaml.parseDocument(docText)

// throws error since expected is an array of one error:
/*
YAMLParseError: Missing , between flow map items at line 6, column 9:

            first: { value: true } # comment,
            second: { value: true }
            ^
*/
assert.deepStrictEqual( docAfter.errors, [])

Expected behaviour
Comma should be in the correct position so that the document still parses after being stringified

Versions (please complete the following information):

• Environment: Node 20.11.1, Firefox 123.0, Edge 122.0.2365.66
• yaml: 2.4.0

Additional context
Add any other context about the problem here.