Rename ES module files to use a .js extension, since Webpack gets confused by .mjs
The file referred to in the package's module field now is compiled down to ES5.
Add a module field to package json file.
Make sure images and links don't render whatever happens to be in node.attrs to the DOM.
Link marks are now non-inclusive by default.
Don't treat <b style=font-weight: normal> as strong when parsing. (Google Docs puts such ridiculous HTML on the clipboard.)
Moved into a separate module.
No longer exports the specs for the nodes and marks separately, since they are now plain objects, not subclasses. They are still exported through nodes and marks objects.
The list-related nodes were moved to the schema-list module.