SDL: Sync SDL wiki -> header (8fb1b)

SDL Commits
1 
From 8fb1b50a9eed9be7254a1200e5f4ab5f147dc2e8 Mon Sep 17 00:00:00 2001
From: SDL Wiki Bot <[EMAIL REDACTED]>
Date: Sat, 20 Aug 2022 17:50:04 +0000
Subject: [PATCH] Sync SDL wiki -> header

---
 include/SDL_render.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/SDL_render.h b/include/SDL_render.h
index 30ef3d6354a..71578ec2098 100644
--- a/include/SDL_render.h
+++ b/include/SDL_render.h
@@ -1765,6 +1765,9 @@ extern DECLSPEC void SDLCALL SDL_DestroyTexture(SDL_Texture * texture);
 /**
  * Destroy the rendering context for a window and free associated textures.
  *
+ * If `window` is NULL, this function will return immediately after setting
+ * the SDL error message to "Invalid window". See SDL_GetError().
+ *
  * \param renderer the rendering context
  *
  * \since This function is available since SDL 2.0.0.