add command to use objects

[mmaulwurff]

https://www.paulfioravanti.com/blog/steno-gaming-doom-typist/#hard-to-use

It seems that it is impossible to open doors or toggle switches (ie use the “Use” functionality) in steno mode. This can be a bit annoying if you encounter multiple enemies immediately after opening a door because:

• you get auto-changed from Exploration Mode to Combat Mode, so you have to change from Gaming mode to Steno mode quickly
• there usually isn’t enough time to defeat all the enemies before the door closes
• you have to switch back to Gaming mode just to re-open the door (since the “simulated” stenotype Enter keystrokes do not register), and then switch back to Steno mode again to resume combat

[paulfioravanti]

Just as an FYI, I currently get around this by using a foot pedal function that exclusively opens doors/triggers "use".