[Diags-Experimental-Formatting] Design updates
[Diags-Experimental-Formatting] Design updates

- Bold diagnostic message text
- Change line numbers and file header to unbolded cyan color to emphazize code snippets/message text
- More compact printing of a single message with unknown location
- If a diagnostic includes excerpts from multiple files, horizontally align the line numbers
- Indent filenames with '=' so they appear to the right of line numbers

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