message: fix(postcss-restructure-variable): add source
diff: -const { Rule } = require("postcss");
  +const postcss = require("postcss");
  function setEquals(a, b) {
  return a.size === b.size && [...a].every((value) => b.has(value));
  @@ -194,16 +194,23 @@ module.exports = (importFrom = []) => {
  }
  });
  + const source = root.source;
  + if (source.end === undefined) {
  + source.end = source.start;
  + }
  +
  const rules = graph.restructure();
  let lastRule = undefined;
  +
  rules.forEach(({ decls, selectors }) => {
  - const rule = new Rule({
  + const rule = postcss.rule({
  selectors: Array.from(selectors),
  + source: source,
  });
  - decls.forEach((value, key) => {
  - rule.append({ prop: key, value: value });
  + decls.forEach((value, prop) => {
  + rule.append({ prop, value, source });
  });
  if (lastRule) {
  