v0.3.0

Added

• The keys Home and End select the first and the last visible node.
• The key Enter dispatches the new event tree.activate, for example to open
  the edit page of the node.
• The options ariaLabel and ariaLabelledBy give the tree an accessible name.
• The colors in tree_element.css are css custom properties, such as
  --tree-element-title-color, so you can change them or add a dark theme. See
  Styling.
• A folder's treeitem has aria-busy="true" while its children load.

Fixed

• The tree can be reached with the tab key when no node is selected.
• Do not set aria-label for tree nodes. Rely on the node text instead.
• Screen readers no longer read the open/close toggler. It has
  aria-hidden="true"; aria-expanded on the node already has the state.
• When loading the children of a folder fails, the tree no longer requests them
  again and again. The folder stays closed; opening it again retries.

Changed

• The toggler and the rows are at least 24px high, and the toggler is at least
  24px wide: the WCAG 2.5.8 minimum for click targets. This makes the tree a
  bit taller. The toggler no longer has a margin; the space around its icon
  separates it from the title.
• The toggler is a span instead of an a without href. Update css that
  selects a.tree-element-toggler.
• When the user prefers reduced motion (prefers-reduced-motion: reduce),
  folders open and close without animation, unless animationSpeed is set.
• The method selectNode keeps an already selected node selected, as
  documented.
• The methods closeNode and toggle return a promise that is resolved when
  the folder is closed or opened, like openNode. Await it when you need to
  know the animation has finished.