Fix tall sprites

[namuol]

Yeah looks like I forgot to implement this; tall sprites just repeat the top sprite:

nessers/nessers-main/src/ppu.rs

Lines 617 to 624 in 1c18f07

	// The tile_id
	tile_id = if y_diff < 8 {
	// Top 8x8 of the 8x16 sprite:
	sprite.tile_id & 0b1111_1110
	} else {
	// Bottom 8x8 of the 8x16 sprite; effectively one full row down:
	sprite.tile_id & 0b1111_1110
	};