[docs] Added trigger events for Vive controls (#2118)
[docs] Added trigger events for Vive controls (#2118)

* [docs] Added trigger events for Vive controls

*Description:*
I noticed that the documentation for Vive controls were missing the `triggerup` and `triggerdown` events. 

*Changes proposed:*
Updated docs with missing events.

* [docs] Removed extra space in event name

* [docs] fixed spacing for Vive controls doc

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