quick comment about potential alternative approaches

(n.b. I've already tried implementing the suggested thing for structs,
but won't link to it here as that commit is almost certainly going
to end up rebased.  Jury's still out on if the idea is good or not.
Seems like the answer is almost certainly "it depends".)

schema/gen/go/genKindList.go

@@ -25,6 +25,8 @@ type generateKindList struct {
 
 func (gk generateKindList) EmitNodeType(w io.Writer) {
 	// Observe that we get a '*' if the values are nullable.
+	//  FUTURE: worth reviewing if this could or should use 'maybe' structs instead of pointers
+	//   (which would effectively trade alloc count vs size for very different performance characteristics).
 	doTemplate(`
 		var _ ipld.Node = {{ .Type | mungeTypeNodeIdent }}{}
 		var _ typed.Node = {{ .Type | mungeTypeNodeIdent }}{}