Add docs for windows DPI awareness hint

[MyreMylar]

After a bit of back and forth in #2081 the best solution seemed to be to document the current behaviour of DPI awareness on windows and revisit this topic in the SDL 3 switchover. Currently in SDL2 DPI awareness is a bit of a mess with different behaviour on different platforms and different APIs in SDL 2.

[MyreMylar]

This is my little test program to play around with DPI in SDL2:

import pygame
import os
import platform

from pygame._sdl2.window import Window


if platform.uname().system == "Windows":
    build_num = int(platform.uname().version.split(".")[2])
    if build_num > 14393:
        os.environ["SDL_WINDOWS_DPI_AWARENESS"] = "permonitorv2"
    elif build_num > 9600:
        os.environ["SDL_WINDOWS_DPI_AWARENESS"] = "permonitor"
    else:
        os.environ["SDL_WINDOWS_DPI_AWARENESS"] = "system"


pygame.init()

window = Window(allow_high_dpi=True)

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

[Temmie3754]

Suitably covers how to easily implement DPI awareness in pygame on windows and other platforms.

[ankith26]

LGTM, thanks for the PR 🎉