Update Trove Classifiers.

Revert to Wagtail 4; it works on both.

Upgrade to PrismJS 1.29.0.

Add setuptools scm.

Update README with links to contributors.

Fix up screenshot for PyPI by using full URL.

Finish up making line numbers optional.

Update README.md

Update README with release notes.

Switch to setuptools_scm. Remove MANIFEST and version.