Adding Block Side Menu Buttons

import "@blocknote/core/fonts/inter.css";import { BlockNoteView } from "@blocknote/mantine";import "@blocknote/mantine/style.css";import {  DragHandleButton,  SideMenu,  SideMenuController,  useCreateBlockNote,} from "@blocknote/react";import { RemoveBlockButton } from "./RemoveBlockButton";export default function App() {  // Creates a new editor instance.  const editor = useCreateBlockNote({    initialContent: [      {        type: "paragraph",        content: "Welcome to this demo!",      },      {        type: "paragraph",        content: "<- Notice the new button in the side menu",      },      {        type: "paragraph",        content: "Click it to remove the hovered block",      },      {        type: "paragraph",      },    ],  });  // Renders the editor instance.  return (    <BlockNoteView editor={editor} sideMenu={false}>      <SideMenuController        sideMenu={(props) => (          <SideMenu {...props}>            {/* Button which removes the hovered block. */}            <RemoveBlockButton />            <DragHandleButton {...props} />          </SideMenu>        )}      />    </BlockNoteView>  );}

import {} from "@blocknote/core";import { SideMenuExtension } from "@blocknote/core/extensions";import {  useBlockNoteEditor,  useComponentsContext,  useExtensionState,} from "@blocknote/react";import { MdDelete } from "react-icons/md";// Custom Side Menu button to remove the hovered block.export function RemoveBlockButton() {  const editor = useBlockNoteEditor();  const Components = useComponentsContext()!;  const block = useExtensionState(SideMenuExtension, {    selector: (state) => state?.block,  });  if (!block) {    return null;  }  return (    <Components.SideMenu.Button      label="Remove block"      icon={        <MdDelete          size={24}          onClick={() => {            editor.removeBlocks([block]);          }}        />      }    />  );}