`lossless: true` option does not preserve trailing spaces in selectors

[ryo-manba]

When using the loseless: true option trailing spaces are removed unexpectedly, even though should be preserved.

Related to stylelint/stylelint#8074 (comment)

Code to Reproduce

const parser = require('postcss-selector-parser');
const selector = ':not(a, )';

console.log('selector:', selector);
parser((selectors) => {
  console.log('parsed:', selectors.toString());
})
  .process(selector, { lossless: true })

Expected

selector: :not(a, )
parsed: :not(a, )

Actual

selector: :not(a, )
parsed: :not(a,)

[alexander-akait]

@ryo-manba pr welcome