Release 4.0.0 - Githubissues

[x] Fix #399
[x] Fix #440
[x] Fix #445
[x] Update dependencies
[x] Update version number in package.json.
[x] Rebuild parser with npm run parser && npm run parser to ensure version at top is correct.
[x] npm run build.
[x] Double check all rolled-up .js files changed correctly
[x] Other tests
[x] Audit CHANGELOG.md, ensuring all changes since last release are reflected
[x] Update release date in CHANGELOG.md
[x] Ensure on main, and that we're clean.
[x] npm pack --dry-run and look for extra files that got included by mistake
[x] Tag: git tag vX.X.X and git push --tags upstream main
[x] npm publish
[x] PR to merge main onto stable
[x] Wait for publish notification. Ensure unpkg and jsdelivr have the latest version.
[x] Merge main->stable PR
[x] Run docs workflow
[x] Create GH release notification, copy in latest portion of CHANGELOG.md
[x] Update CHANGELOG.md with skeleton for next release

peggyjs / peggy