Explicitly note coercion to string for .contains (#1413)
Explicitly note coercion to string for .contains (#1413)

* Explicitly note coercion to string for .contains

as per #992

* make link to traps more specific.

as per review

* Address comments

Address code review comments
   * remove some trailing whitespace 
   * add more examples
   * remove redundancy

perl6/doc,dmaestro/doc,gfldex/doc,MasterDuke17/doc,dmaestro/doc,stmuk/doc,gfldex/doc,perl6/doc,jonathanstowe/doc,dmaestro/doc,MasterDuke17/doc,gfldex/doc,jonathanstowe/doc,MasterDuke17/doc,stmuk/doc,jonathanstowe/doc,antquinonez/doc,perl6/doc,tbrowder/doc,jonathanstowe/doc,jonathanstowe/doc,tbrowder/doc,MasterDuke17/doc,dmaestro/doc,stmuk/doc,tbrowder/doc,tbrowder/doc,dmaestro/doc,antquinonez/doc,stmuk/doc,gfldex/doc,perl6/doc,antquinonez/doc,gfldex/doc,antquinonez/doc,antquinonez/doc,perl6/doc,stmuk/doc