Incomplete list of supported controllers in docs

[claremacrae]

Hi Tom,

Thanks for an awesome library! I read the docs cover-to-cover this morning, and noticed this small inconsistency....

This section says: "currently there are six supported controllers:" https://approxeng.github.io/approxeng.input/howtouse.html?highlight=six%20supported%20controllers#constructing-and-binding-a-controller

Whereas this page has pictures of 8 controllers, but has links to 9 of them. https://approxeng.github.io/approxeng.input/index.html

1. Could the missing ones be added to howtouse.html?

2. I wonder whether in the following doc for adding new controllers, it might be worth listing documentation pages that need to be updated.. https://approxeng.github.io/approxeng.input/addingcontrollers.html

I guess it could link to:

• https://approxeng.github.io/approxeng.input/simpleusage.html#button-names
• https://approxeng.github.io/approxeng.input/howtouse.html?highlight=six%20supported%20controllers#constructing-and-binding-a-controller
• adding a new page, such as https://approxeng.github.io/approxeng.input/api/pihut.html