message: Avoid `master` noise in `highlight-non-default-base-branch`
  Fixes
diff: @@ -13,6 +13,10 @@ interface BranchInfo {
  baseRefName: string;
  }
  +function isClosed(prLink: HTMLElement): boolean {
  + return Boolean(prLink.closest('.js-issue-row')!.querySelector('.octicon.merged, .octicon.closed'));
  +}
  +
  function buildQuery(issueIds: string[]): string {
  return `
  repository() {
  @@ -44,6 +48,12 @@ async function init(): Promise<false | void> {
  continue;
  }
  + // Avoid noise on old PRs pointing to `master` #3910
  + // If the PR is open, it means that `master` still exists
  + if (pr.baseRefName === 'master' && isClosed(prLink)) {
  + continue;
  + }
  +
  const branch = pr.baseRef && buildRepoURL(`tree/${pr.baseRefName}`);
  prLink.parentElement!.querySelector('.text-small.text-gray')!.append(
  