Removed incorrect documentation for SDL_RenderViewportSet()

Closes https://github.com/libsdl-org/SDL/pull/12854

(cherry picked from commit c076b0d17f2ed92a72b5d155d1613ebfbb3073df)

include/SDL3/SDL_render.h

@@ -1607,8 +1607,7 @@ extern SDL_DECLSPEC bool SDLCALL SDL_GetRenderViewport(SDL_Renderer *renderer, S
  * Return whether an explicit rectangle was set as the viewport.
  *
  * This is useful if you're saving and restoring the viewport and want to know
- * whether you should restore a specific rectangle or NULL. Note that the
- * viewport is always reset when changing rendering targets.
+ * whether you should restore a specific rectangle or NULL.
  *
  * Each render target has its own viewport. This function checks the viewport
  * for the current render target.