[rcore] `IsKeyPressed()` missing quick inputs

[exformation]

For me, IsKeyPressed fails to see a press if the release happens immediately afterwards.

My keyboard firmware sends some keys as:

register_key(key);
unregister_key(key);

with no delay between them by default. Raylib doesn't see these presses (unless I double tap the key or increase the firmware's tap delay). I know this is because of my keyboard firmware, but the key has been pressed, so Raylib should still see it. Other applications/games don't have issues with this, and qmk is a very popular firmware, so more people will run into this issue in the future.