Fix windowevent and key repeat in sdl2-compat

[ankith26]

WINDOWEVENT translation was broken when compiled with sdl2-compat.

The issue was in our _pg_translate_windowevent function. The current code was directly modifying the event type there but it seems like it is simply an implementation detail that we were relying on, and one isn't supposed to actually modify events in SDL_FilterEvents based filtering. Plus, this is easier to fix on our side than fix on sdl2-compat side.

I also took the opportunity to improve the comments while I was giving the implementation a good think.

This fixes a failing unit test so I don't see the need to add more tests here.

UPDATE: key repeat was broken and for similar reasons, I have fixed that here as well.

[ankith26]

from @Starbuck5 in #3287

In python -m pygame.examples.video neither of the two windows can be exited by clicking the x button. (Probably related to whatever it didn't like about the event watch?)

This PR should fix the issue.

[ankith26]

import pygame
import sys

pygame.init()
screen = pygame.display.set_mode((400, 200), pygame.RESIZABLE)
pygame.display.set_caption("Key Repeat & Block Test")
clock = pygame.time.Clock()
font = pygame.font.Font(None, 36)

counter = 0
key_repeat_on = True
key_blocked_on = False

pygame.key.set_repeat(300, 100)

running = True
while running:
    screen.fill((30, 30, 30))

    text = font.render(f"Counter: {counter}", True, (255, 255, 255))
    info1 = font.render(f"Repeat: {'ON' if key_repeat_on else 'OFF'}", True, (180, 180, 180))
    info2 = font.render(f"Blocked: {'YES' if key_blocked_on else 'NO'}", True, (180, 180, 180))

    screen.blit(text, (50, 40))
    screen.blit(info1, (50, 90))
    screen.blit(info2, (50, 130))
    
    pygame.display.flip()

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

        elif event.type == pygame.KEYDOWN:
            print(f"KEYDOWN: {pygame.key.name(event.key)}")

            if event.key == pygame.K_SPACE:
                counter += 1

            elif event.key == pygame.K_r:
                key_repeat_on = not key_repeat_on
                if key_repeat_on:
                    pygame.key.set_repeat(300, 100)
                else:
                    pygame.key.set_repeat()

        elif event.type == pygame.MOUSEBUTTONDOWN:
            key_blocked_on = not key_blocked_on
            if key_blocked_on:
                pygame.event.set_blocked(pygame.KEYDOWN)
            else:
                pygame.event.set_allowed(pygame.KEYDOWN)

        elif event.type >= pygame.WINDOWSHOWN and event.type <= pygame.WINDOWDISPLAYCHANGED:
            print(event)

    clock.tick(60)

pygame.quit()
sys.exit()

test script for this PR