Use better example for Date.new(Instant)
Use better example for Date.new(Instant)

- it's not obvious that `now` is an Instant
- some may wonder how to turn a Unix time stamp into Date
MasterDuke17/doc,dmaestro/doc,dmaestro/doc,stmuk/doc,gfldex/doc,gfldex/doc,jonathanstowe/doc,stmuk/doc,antquinonez/doc,jonathanstowe/doc,tbrowder/doc,perl6/doc,antquinonez/doc,antquinonez/doc,stmuk/doc,tbrowder/doc,MasterDuke17/doc,perl6/doc,dmaestro/doc,gfldex/doc,antquinonez/doc,antquinonez/doc,tbrowder/doc,perl6/doc,perl6/doc,gfldex/doc,dmaestro/doc,jonathanstowe/doc,MasterDuke17/doc,stmuk/doc,stmuk/doc,tbrowder/doc,jonathanstowe/doc,dmaestro/doc,perl6/doc,gfldex/doc,MasterDuke17/doc,jonathanstowe/doc