JavaFX is missing a rich text control like JEditorPane/StyledDocument.

While a number of open source projects exists [0], [1], it would be nice to have such a control included in the core, which either supports most of the desired functionality out of the box, or can be extended easily to support additional requirements.

The exact list of features is TBD at this moment, but it should be possible to:

- use large (but narrow) text models
- easily extend the base control to add custom elements, line numbers, markers, etc.
- custom highlights and spell checker squiggly lines
- keyboard and mouse navigation, with possibility of custom navigation (such as skipping non-editable sections)
- rich text copy/paste
- "size to content" mode that turns off the scroll bars
- custom tab size (custom tab stops will not be supported)
- multiple views connected to the same model
- styling via CSS or direct style
- single selection (multiple selection or rectangular selection will not be supported)

The first step is to analyze possible missing APIs - see JDK-8300569


NOTES

Third party projects:
[0] https://github.com/FXMisc/RichTextFX
[1] https://github.com/gluonhq/rich-text-area
[2] https://github.com/andy-goryachev/FxEditor

TODO
- don't forget to update javadoc for TextArea where it mentions rich text editing.