fix: pac-man doesnt run in the first line

[horw]

This PR addresses an issue related to the initial execution of scripts in small terminal windows.
If there isn't enough vertical space for the full Pac-Man animation, we set diff_y to 0.

[horw]

Also found another bug with width, actually it is 29,but your width shows as ~88, you can check it

screenshot after fixing:

[horw]

fmt.Printf("\033[%d;%dH%s", y+k+1, x, strings.Repeat(" ", width))

What do you think about this width? When it is equal to Pac-Man's size, it doesn't look very smooth, but if you add just 3-5 symbols, it looks much better.

[orangekame3]

Thank you for your contribution! 🎉

I'll check it this weekend.

[orangekame3]

@horw
Thank you for PR!
#19 (review)
this comment is also LGTM, I add 3 more symbol.