SDL: Sync wiki -> header (4d0c3)

SDL Commits
1 
From 4d0c3cb2a8323438e2593d832d9478d663487417 Mon Sep 17 00:00:00 2001
From: SDL Wiki Bot <[EMAIL REDACTED]>
Date: Fri, 17 Sep 2021 19:17:05 +0000
Subject: [PATCH] Sync wiki -> header

---
 include/SDL_system.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/SDL_system.h b/include/SDL_system.h
index 5f12787c0d..6dd5c48d97 100644
--- a/include/SDL_system.h
+++ b/include/SDL_system.h
@@ -50,6 +50,8 @@ typedef void (SDLCALL * SDL_WindowsMessageHook)(void *userdata, void *hWnd, unsi
  *
  * \param callback The SDL_WindowsMessageHook function to call.
  * \param userdata a pointer to pass to every iteration of `callback`
+ *
+ * \since This function is available since SDL 2.0.16.
  */
 extern DECLSPEC void SDLCALL SDL_SetWindowsMessageHook(SDL_WindowsMessageHook callback, void *userdata);
 
@@ -95,6 +97,8 @@ typedef struct ID3D11Device ID3D11Device;
  * \param renderer the renderer from which to get the associated D3D11 device
  * \returns the D3D11 device associated with given renderer or NULL if it is
  *          not a D3D11 renderer; call SDL_GetError() for more information.
+ *
+ * \since This function is available since SDL 2.0.16.
  */
 extern DECLSPEC ID3D11Device* SDLCALL SDL_RenderGetD3D11Device(SDL_Renderer * renderer);