Replace "unchecked" arithmetic with "wrapping" in optimization guide. (#31463)
Replace "unchecked" arithmetic with "wrapping" in optimization guide. (#31463)

* Replace "unchecked" arithmetic with "wrapping" in optimization guide.

Previously, this section talked about "unchecked" arithmetic operations; that's not what &+ and friends are. They are wrapping operations with fully-defined behavior (unlike nsw llvm ops, which are actually "unchecked").

* Update docs/OptimizationTips.rst
stephentyrone/swift,xwu/swift,stephentyrone/swift,jmgc/swift,tkremenek/swift,glessard/swift,nathawes/swift,allevato/swift,tkremenek/swift,rudkx/swift,atrick/swift,rudkx/swift,tkremenek/swift,gregomni/swift,aschwaighofer/swift,glessard/swift,benlangmuir/swift,JGiola/swift,CodaFi/swift,aschwaighofer/swift,jmgc/swift,roambotics/swift,atrick/swift,harlanhaskins/swift,airspeedswift/swift,tkremenek/swift,airspeedswift/swift,stephentyrone/swift,tkremenek/swift,gregomni/swift,parkera/swift,atrick/swift,jckarter/swift,hooman/swift,parkera/swift,allevato/swift,CodaFi/swift,hooman/swift,glessard/swift,benlangmuir/swift,tkremenek/swift,roambotics/swift,CodaFi/swift,xwu/swift,apple/swift,JGiola/swift,nathawes/swift,harlanhaskins/swift,stephentyrone/swift,allevato/swift,rudkx/swift,allevato/swift,xwu/swift,apple/swift,airspeedswift/swift,atrick/swift,roambotics/swift,ahoppen/swift,glessard/swift,JGiola/swift,parkera/swift,CodaFi/swift,nathawes/swift,allevato/swift,hooman/swift,jmgc/swift,glessard/swift,allevato/swift,xwu/swift,xwu/swift,stephentyrone/swift,rudkx/swift,roambotics/swift,roambotics/swift,apple/swift,harlanhaskins/swift,harlanhaskins/swift,stephentyrone/swift,gregomni/swift,ahoppen/swift,JGiola/swift,tkremenek/swift,glessard/swift,aschwaighofer/swift,JGiola/swift,parkera/swift,jmgc/swift,gregomni/swift,harlanhaskins/swift,CodaFi/swift,gregomni/swift,nathawes/swift,ahoppen/swift,benlangmuir/swift,benlangmuir/swift,airspeedswift/swift,CodaFi/swift,hooman/swift,aschwaighofer/swift,hooman/swift,allevato/swift,rudkx/swift,benlangmuir/swift,nathawes/swift,airspeedswift/swift,jmgc/swift,xwu/swift,roambotics/swift,apple/swift,jckarter/swift,CodaFi/swift,airspeedswift/swift,jckarter/swift,parkera/swift,nathawes/swift,hooman/swift,harlanhaskins/swift,jmgc/swift,jckarter/swift,atrick/swift,rudkx/swift,nathawes/swift,aschwaighofer/swift,JGiola/swift,xwu/swift,jckarter/swift,airspeedswift/swift,atrick/swift,apple/swift,aschwaighofer/swift,benlangmuir/swift,stephentyrone/swift,aschwaighofer/swift,parkera/swift,harlanhaskins/swift,parkera/swift,jckarter/swift,jckarter/swift,gregomni/swift,ahoppen/swift,ahoppen/swift,ahoppen/swift,hooman/swift,apple/swift,parkera/swift,jmgc/swift