Add SELECT button to video UI controls list

Author: RocketRobz

README.md

@@ -22,6 +22,7 @@ To play videos, you'll need to convert them to the Rocket Video (`.rvid`) format
 - D-Pad `Left`/`Right`: Jump 5 seconds (30 seconds with `R` shoulder held)
 - D-Pad `Down`/`Up`: Jump 10 seconds (1 minute with `R` shoulder held)
 - D-Pad `Left`+`Down`/`Up`+`Right`: Jump 15 seconds (2 minutes with `R` shoulder held)
+- `SELECT`: Turn off/on bottom screen backlight (only applies to single-screen videos)
 - `B` or touch `Return`: Exit video
 
 # Credits