Add custom CSS class and Prosemirror drop-down for sidebar style

[cyface]

Something like:

Hooks.on("getProseMirrorMenuDropDowns", (menu, items) => {
  const wrapIn = ProseMirror.commands.wrapIn;
  if ("format" in items) {
    items.format.entries.push({
      action: "custom",
      title: "Custom Styles",
      children: [
        {
          action: "highlight",
          title: "Highlight Text",
          node: menu.schema.nodes.paragraph,
          attrs: { class: "sidebar" },
          cmd: () => {
            menu._toggleBlock(menu.schema.nodes.paragraph, wrapIn, {
              attrs: { _preserve: { class: "sidebar" } },
            });
            return true;
          },
        },
        // Add more styles as needed
      ],
    });
  }
});