Demo should not expect tl.store() return value

[CityBoy-Claude]

Thanks for making these puzzles, they are super helpful for Triton beginners!

The tl.store demo appears to expect a return value from tl.store(), but the function does not return anything. As a Triton beginner, this was confusing at first. It would be better to remove that part.

@triton_viz.trace("tracer")
@triton.jit
def demo(z_ptr):
    range = tl.arange(0, 8)
    z = tl.store(z_ptr + range, 10, range < 5)
    print(z)