blockContent.formats - mapping from a format type (e.g. a, strong) to
a custom component that will render that format.
Format components should take at least children and RichText props, and
should render <RichText content={ children } /> somewhere.
NPM scripts
build - runs all build subtasks below
build:commonjs - builds CommonJS modules for distribution
build:es - builds ES6 modules for distribution
clean - cleans up all built resources
clean:coverage - cleans up coverage reports
clean:dist - cleans up compiled files for distribution
clean:docs - cleans up built documentation
docs - builds API documentation
lint - lints all sources
test - executes tests (add --watch to watch for changes)