Add support for page breaks?

[jenstroeger]

Using Word or Writer one can insert a page break by pressing Ctrl + Enter (Windows) or Cmd + Enter (Mac). Would you be open to adding an event 'newpage' (similar to the existing 'newline') to the dispatcher here

editable.js/src/dispatcher.js

Lines 271 to 276 in 974196a

	.on('shiftEnter', function (event) {
	event.preventDefault()
	event.stopPropagation()
	const cursor = self.selectionWatcher.forceCursor()
	self.notify('newline', this, cursor)
	})

which refines the key.enter event here

editable.js/src/keyboard.js

Lines 45 to 47 in 974196a

	case this.key.enter:
	if (event.shiftKey) return this.notify(target, 'shiftEnter', event)
	return this.notify(target, 'enter', event)

with

if (event.shiftKey) return this.notify(target, 'shiftEnter', event)
else if (navigator.platform.startsWith('Win') and event.ctrlKey) return this.notify(target, 'cmdEnter', event)
else if (event.metaKey) return this.notify(target, 'cmdEnter', event)

Happy to provide a PR with tests and documentation.