Make the whiteboard better

The brushes of the whiteboard can be increased, and it is supported to directly link two blocks with a brush. It is more convenient to link them as long as you stop for a while. In addition, it is inconvenient to have only straight lines for the connecting lines, and there are no braces or straight line tools to draw directly by yourself. If there are these functions, the whiteboard can make more beautiful graphics. Hope to get better and better logseq