Cleanup of old issues and PRs

[cyrgani]

This is an issue to list old issues and PRs that should have been closed or merged a long time ago, because the thing they are trying to fix no longer exists or was fixed already elsewhere. I will update it whenever I see another obsolete item.

Obsolete PRs that should be closed

• Let anyone get the DPI scale #609: this feature exists already, as macroquad::window::screen_dpi_scale()
• Fix constant sample_count #42: the sample_count is no longer set to 4 anywhere
• A simple missile command game clone from 80s Atari. #536 and Fix for CI fmt fix error #537: both contain the same code, at least one should be closed
• Fix 'attempt to add with overflow' in draw_poly #493: this no longer overflows with sides = 255 since 0..=sides is used instead of 0..sides + 1