Fixed stray end of line blanks, added comments in .editorconfig, tweaked some headers.

imgui.cpp

@@ -4152,7 +4152,7 @@ void ImGui::EndFrame()
 {
     ImGuiContext& g = *GImGui;
     IM_ASSERT(g.Initialized);
-    
+
     // Don't process EndFrame() multiple times.
     if (g.FrameCountEnded == g.FrameCount)
         return;