Trim trailing white spaces. Changes some NULL to nullptr.

imgui_tables.cpp

@@ -631,7 +631,7 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     // At this point the ->NameOffset field of each column will be invalid until TableUpdateLayout() or the first call to TableSetupColumn()
     if (table->ColumnsNames.Buf.Size > 0)
         table->ColumnsNames.Buf.resize(0);
-    
+
     return true;
 }