(03) ticket_v1 - (09) heap outdated reference

[lundybernard]

Exercise (03) ticket_v1 - (09) heap references the "Data layout" section of the Rustonomicon

The Data layout section currently reads:
"This chapter is ideally in agreement with, and rendered redundant by, the Type Layout section of the Reference. When this book was first written, the reference was in complete disrepair, and the Rustonomicon was attempting to serve as a partial replacement for the reference. This is no longer the case, so this whole chapter can ideally be deleted."

The link may need to be updated now or in the near future.