Fix TOC entry for Linux in GettingStarted
Fix TOC entry for Linux in GettingStarted

The TOC was referencing a no longer existing "Ubuntu Linux" section.
atrick/swift,benlangmuir/swift,apple/swift,apple/swift,rudkx/swift,apple/swift,roambotics/swift,xwu/swift,xwu/swift,atrick/swift,benlangmuir/swift,gregomni/swift,rudkx/swift,xwu/swift,xwu/swift,ahoppen/swift,gregomni/swift,atrick/swift,ahoppen/swift,glessard/swift,rudkx/swift,roambotics/swift,gregomni/swift,atrick/swift,glessard/swift,gregomni/swift,gregomni/swift,xwu/swift,xwu/swift,JGiola/swift,benlangmuir/swift,glessard/swift,glessard/swift,benlangmuir/swift,JGiola/swift,atrick/swift,roambotics/swift,atrick/swift,xwu/swift,roambotics/swift,JGiola/swift,JGiola/swift,rudkx/swift,apple/swift,roambotics/swift,gregomni/swift,rudkx/swift,roambotics/swift,benlangmuir/swift,glessard/swift,apple/swift,ahoppen/swift,apple/swift,ahoppen/swift,glessard/swift,rudkx/swift,ahoppen/swift,JGiola/swift,ahoppen/swift,benlangmuir/swift,JGiola/swift