Fixed PSDraw rectangle

[radarhere]

Resolves #6428

Uses the changes suggested in that issue. I can't see a way to add tests for this.

Moving the neg means that instead of going from (0, 0) to (width, 0), (width, -height), (0, -height) and (0, 0),
it instead goes from (0, 0) to (width, 0), (width, height), (0, height) and (0, 0),
so instead of drawing the rectangle below the starting point, it draws it above.