update the readme with examples to use @if
update the readme with examples to use @if

rphuber/dustjs,jbcpollak/dustjs,alihalabyah/dustjs,mobify/dustjs,tachyon1337/dustjs,linkedin/dustjs,cake-disposal-squad/dustjs,ellipticaljs/dustjs,ellipticaljs/dustjs,eugeneai/dustjs,cake-disposal-squad/dustjs,jrrbru/dustjs,jimmyhchan/dustjs,erg0dic/dustjs,modulexcite/dustjs,aredridel/dustjs,tachyon1337/dustjs,sethkinast/dustjs,shakyShane/crossbow-lang,jimmyhchan/dustjsMirrorOld,nchlswtsn/dustjs,modulexcite/dustjs,alihalabyah/dustjs,catberry/catberry-dust,jbcpollak/dustjs