Viewports: added GetWindowViewport() in imgui_internal.h to increase consistency with code using this public API in docking branch. (#9140)

imgui_internal.h

diff --git a/imgui_internal.h b/imgui_internal.h
index 3cc3ef5..e8618cc 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -3223,6 +3223,7 @@
     IMGUI_API void          UpdateMouseMovingWindowEndFrame();
 
     // Viewports
+    inline ImGuiViewport*   GetWindowViewport() { return GetMainViewport(); } // For code consistency. This is public API in docking branch.
     IMGUI_API void          ScaleWindowsInViewport(ImGuiViewportP* viewport, float scale);
     IMGUI_API void          SetWindowViewport(ImGuiWindow* window, ImGuiViewportP* viewport);