* Fix spell check bug by add data-text:true
* Fix spell check bug by spell check add length to a leaf
* Fix tests to use data-text:true for marks
* Rename data-text to data-slate-leaf; Remove setRef; unlift attributes in leaf
* Update examples with data-*
* Add attributes to document
* Fix renderMark in all documents
* Prettier markdown
* Add Prettier, with basic config and ESLint integration
* Apply Prettier to all files using `yarn lint --fix`
* Tell Prettier to ignore an empty text in a test output.
* Run Prettier on JS files not handled by ESLint, and lint them too
* rename state to value in slate core, as deprecation
* rename all references to state to value in slate core
* migrate slate-base64-serializer
* migrate slate-html-serializer
* migrate slate-hyperscript
* migrate slate-plain-serializer
* migrate slate-prop-types
* migrate slate-simulator
* fix change.setState compat
* deprecate references to state in slate-react
* remove all references to state in slate-react
* remove `value` and `schema` from props to all components
* fix default renderPlaceholder
* fix tests
* update examples
* update walkthroughs
* update guides
* update reference