SDL: Document the packed integer formats SDL_Color is bit-compatible with.

SDL Commits
1 
From 7f5339e6c4dad8c99a3a8af4fd0c843c5b39caca Mon Sep 17 00:00:00 2001
From: Alex Szpakowski <[EMAIL REDACTED]>
Date: Tue, 14 Dec 2021 14:24:59 -0400
Subject: [PATCH] Document the packed integer formats SDL_Color is
 bit-compatible with.

---
 include/SDL_pixels.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/SDL_pixels.h b/include/SDL_pixels.h
index fcfd649c5b5..5f859fefc0d 100644
--- a/include/SDL_pixels.h
+++ b/include/SDL_pixels.h
@@ -301,6 +301,11 @@ typedef enum
         SDL_DEFINE_PIXELFOURCC('O', 'E', 'S', ' ')
 } SDL_PixelFormatEnum;
 
+/**
+ * The bits of this structure can be directly reinterpreted as an integer-packed
+ * color which uses the SDL_PIXELFORMAT_RGBA32 format (SDL_PIXELFORMAT_ABGR8888
+ * on little-endian systems and SDL_PIXELFORMAT_RGBA8888 on big-endian systems).
+ */
 typedef struct SDL_Color
 {
     Uint8 r;