Attempt to document confusion around infix operator assignment.
Attempt to document confusion around infix operator assignment.

This was in #perl6 today; first pass at documenting a potential trap.

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