Scanvideo: hpulse for 640x480

[ikjordan]

In vga_modes.c line 428 h_pulse is set to 64. This results in my monitor displaying the screen image shifted, resulting in pixels on the right hand side of the image not being displayed.

Should it be set to 96? Other sources, e.g.
http://tinyvga.com/vga-timing/640x480@60Hz
https://vanhunteradams.com/Pico/VGA/VGA.html#Video-explanation
https://gregchadwick.co.uk/blog/playing-with-the-pico-pt5/
indicate this.

When I change the value to 96 my monitor displays the full screen image correctly

[CHiPs44]

I also use 96 in my https://github.com/CHiPs44/hagl_pico_vgaboard/blob/develop/include/pico-vgaboard-modes-640x480.h#L66, but it comes from TinyVGA.