function getLineEmptyIndent(sourceCode, token) {
  const LT_CHAR = /[\n\r\u2028\u2029]/
  const EMPTY_CHAR = /\s/
  const text = sourceCode.text
  let i = token.range[0] - 1

  while (i >= 0 && !LT_CHAR.test(text[i])) {
    i -= 1
  }
  let j = i
  while (EMPTY_CHAR.test(text[j])) {
    j += 1
  }

  return text.slice(i + 1, j)
}
Get the text of the empty indentation part of the line which the given token is on.
@param {SourceCode} sourceCode the source code object
@param {Token} token the token to get the indentation text of the line which the token is on
@returns {string} The text of indentation part.