setMousePointer method
Sets the mouse pointer shape to the specified pointer type.
Note: This uses the OSC 22 escape sequence, which is supported by some
modern terminal emulators (such as Kitty or xterm), but is ignored
by others (such as iTerm2 or Windows Terminal).
Implementation
void setMousePointer(MousePointer pointer) {
backend.write('\x1b]22;${pointer.value}\x1b\\');
}