sway.1.scd: document environment vars set by sway
sway.1.scd: document environment vars set by sway

This just documents the few environment variables set by sway in
sway.1.scd

ascent12/sway,1ace/sway,1ace/sway,ascent12/sway,1ace/sway,SirCmpwn/sway,ascent12/sway