Docs/SourceKit: add some documentation for expression type request.
Docs/SourceKit: add some documentation for expression type request.

xwu/swift,jmgc/swift,sschiau/swift,practicalswift/swift,atrick/swift,xedin/swift,xedin/swift,ahoppen/swift,nathawes/swift,glessard/swift,practicalswift/swift,devincoughlin/swift,benlangmuir/swift,devincoughlin/swift,practicalswift/swift,aschwaighofer/swift,practicalswift/swift,airspeedswift/swift,airspeedswift/swift,parkera/swift,gregomni/swift,lorentey/swift,practicalswift/swift,jmgc/swift,parkera/swift,shahmishal/swift,airspeedswift/swift,harlanhaskins/swift,apple/swift,JGiola/swift,lorentey/swift,rudkx/swift,tkremenek/swift,glessard/swift,harlanhaskins/swift,harlanhaskins/swift,karwa/swift,JGiola/swift,nathawes/swift,CodaFi/swift,gribozavr/swift,glessard/swift,tkremenek/swift,aschwaighofer/swift,benlangmuir/swift,apple/swift,hooman/swift,devincoughlin/swift,rudkx/swift,harlanhaskins/swift,apple/swift,hooman/swift,JGiola/swift,gribozavr/swift,karwa/swift,jmgc/swift,CodaFi/swift,nathawes/swift,sschiau/swift,glessard/swift,parkera/swift,stephentyrone/swift,nathawes/swift,atrick/swift,jckarter/swift,parkera/swift,xwu/swift,parkera/swift,atrick/swift,airspeedswift/swift,ahoppen/swift,shajrawi/swift,harlanhaskins/swift,sschiau/swift,CodaFi/swift,benlangmuir/swift,tkremenek/swift,CodaFi/swift,roambotics/swift,aschwaighofer/swift,shahmishal/swift,shajrawi/swift,xwu/swift,allevato/swift,rudkx/swift,karwa/swift,gregomni/swift,ahoppen/swift,gribozavr/swift,shajrawi/swift,lorentey/swift,benlangmuir/swift,atrick/swift,roambotics/swift,sschiau/swift,parkera/swift,practicalswift/swift,CodaFi/swift,shajrawi/swift,atrick/swift,nathawes/swift,shahmishal/swift,lorentey/swift,hooman/swift,atrick/swift,stephentyrone/swift,parkera/swift,stephentyrone/swift,gregomni/swift,gribozavr/swift,rudkx/swift,shahmishal/swift,aschwaighofer/swift,karwa/swift,JGiola/swift,roambotics/swift,apple/swift,nathawes/swift,allevato/swift,jckarter/swift,karwa/swift,shajrawi/swift,xedin/swift,xwu/swift,airspeedswift/swift,rudkx/swift,jmgc/swift,shahmishal/swift,sschiau/swift,apple/swift,practicalswift/swift,karwa/swift,lorentey/swift,allevato/swift,xedin/swift,lorentey/swift,gregomni/swift,jckarter/swift,gregomni/swift,devincoughlin/swift,stephentyrone/swift,stephentyrone/swift,gregomni/swift,shahmishal/swift,tkremenek/swift,hooman/swift,xwu/swift,tkremenek/swift,jckarter/swift,allevato/swift,ahoppen/swift,ahoppen/swift,sschiau/swift,glessard/swift,roambotics/swift,practicalswift/swift,CodaFi/swift,xwu/swift,sschiau/swift,apple/swift,allevato/swift,benlangmuir/swift,devincoughlin/swift,devincoughlin/swift,roambotics/swift,xedin/swift,jckarter/swift,benlangmuir/swift,aschwaighofer/swift,ahoppen/swift,hooman/swift,rudkx/swift,hooman/swift,airspeedswift/swift,xwu/swift,glessard/swift,airspeedswift/swift,sschiau/swift,xedin/swift,devincoughlin/swift,shajrawi/swift,hooman/swift,parkera/swift,jmgc/swift,shajrawi/swift,jmgc/swift,JGiola/swift,gribozavr/swift,lorentey/swift,harlanhaskins/swift,allevato/swift,stephentyrone/swift,aschwaighofer/swift,gribozavr/swift,shahmishal/swift,harlanhaskins/swift,nathawes/swift,jckarter/swift,xedin/swift,karwa/swift,shahmishal/swift,tkremenek/swift,devincoughlin/swift,aschwaighofer/swift,lorentey/swift,allevato/swift,jmgc/swift,JGiola/swift,roambotics/swift,karwa/swift,xedin/swift,shajrawi/swift,CodaFi/swift,tkremenek/swift,gribozavr/swift,jckarter/swift,stephentyrone/swift,gribozavr/swift