Update `/pager sup` to only show your assigned tickets

[technicalpickles]

Since #4, ack and resolve will only act on your own incidents by default. They support ack! and resolve! to disregard that.

I think it'd make sense to keep parity of those for /pager sup to list only your things, with a ! version listing them all.

[technicalpickles]

This would also mirror the newish behavior on pagerduty.com, where you see your incidents first by default.