fix spec for Xcode install instructions
fix spec for Xcode install instructions

mbogh/jazzy,emiscience/jazzy,emiscience/jazzy,mbogh/jazzy,agentk/jazzy,johndpope/jazzy,pcantrell/jazzy,1ec5/jazzy,jeeftor/jazzy,1ec5/jazzy,PSPDFKit-labs/jazzy,realm/jazzy,pcantrell/jazzy,jeeftor/jazzy,Kapeli/jazzy,agentk/jazzy,realm/jazzy,pcantrell/jazzy,Kapeli/jazzy,johndpope/jazzy,1ec5/jazzy,mbogh/jazzy,emiscience/jazzy,Kapeli/jazzy,jeeftor/jazzy,johndpope/jazzy,PSPDFKit-labs/jazzy,agentk/jazzy