Make help dialog context sensitive to device and input choice

[kbauer]

The help mentions how to use a teleport feature with a controller, but an X-input gamepad isn't recognized and nothing indicates how, if at all, the feature is available with mouse and keyboard.

Movement and mouselook remain unexplained too, but follow common conventions, so that's less of a problem.

┆Issue is synchronized with this Jira Task

[gfodor]

If you don't mind, would you rename this ticket to "Update Help to be context-sensitive" -- I think we want to do a significant pass on the Help dialog so that it delivers the proper information for your device and platform combination -- control schemes are just one of the things that would vary.

[gfodor]

Also thank you for the ticket!