Summary of the new feature/enhancement

When setting the cursor shape to filledBox or vintage, it would be nice if you could round the corners of that shape.

Proposed technical implementation details (optional)

If the cursor is drawn from a shape, then you could add a setting for cursorCornerRadius: "2, 2, 2, 2" and apply that to the shape. If however the cursor image is drawn from a font in the glyph - then perhaps CascadiaCode could have rounded boxes for the cursors.