Add gridlines to graphs for easier counting

[marquizzo]

It's a bit difficult to tell where the right-most data-points land on the vertical axis. Does the latest Edge breach the 5,800 API count? Is it closer to 5,750? It's very hard to tell! If the chart had horizontal gridlines on each tick-mark, it would be much easier and accurate to read at a quick glance.

[foolip]

Hi @marquizzo, thanks for the suggestion! I agree that would be better, but unfortunately Web API Confluence isn't being maintained much. In fact there have been no new browser releases uploaded in almost a year.

I would be happy to review a pull request adding gridlines, but can't spend time on doing it myself.