Add slingshotting from ultimate#1860

While this doesn’t affect most characters a ton, on clairen, the lack of slingshots is deeply felt. Being unable to turn around in your initial dash without also dashing back makes it impossible to do quick turnaround bairs, and ends up making the game feel clunky to someone accustomed to slingshotting. If it was added only on diagonal back inputs, it wouldn’t have to affect dashdancing at all.

We have it. It’s called RAR.

RAR is different, as it doesn’t work in the initial dash. Slingshotting allows a full momentum forward bair during the initial dash, while a rar only works after the initial dash.