* rough starting point, roving tabindex in toolbar, bold and italic buttons
* refactor, add link
* add ul
* add ordered list
* core formatters in place, wip
* overflow options
* add keyboard shortcuts
* tidy up some dodgy classes
* add mocks for runtime in test and storybook, use correct modifier key for tooltip
* style tweaks
* refactor tooltips
* add markdown formatters tests
* add tests for toolbar component, fix mistake in overflow menu tooltips
* undo change no longer needed to button
* fix issue accessing runtime in formatters file
* only show darkened buttons and tooltips when focus-visible is true
* mobile view
* fix for responsive buttons & roving tabindex
* tweaks from PR review
* update cursor position on link insertion
* add a new line after block selection formatting
* align icons in center
* tidy up overflow menu listeners
* small refactors
* test for new text area util
* tidy up new lines after syntaxes
* fix logic in cursor offsets for links
* prevent scroll jumps after inserting syntax
* some style tweaks
* insert level 2 heading with new lines above and below
* update icons
* use margin instead of gap
