Comments: fixed missing line in the "how a simple rendering function may look like" section (#2258)

imgui.cpp

@@ -259,6 +259,7 @@ CODE
        // TODO: Setup shader: vertex { float2 pos, float2 uv, u32 color }, fragment shader sample color from 1 texture, multiply by vertex color.
        for (int n = 0; n < draw_data->CmdListsCount; n++)
        {
+          const ImDrawList* cmd_list = draw_data->CmdLists[n]; 
           const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;  // vertex buffer generated by ImGui
           const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;   // index buffer generated by ImGui
           for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)