docs(tour) chapter

tour/chapter.go

@@ -2,13 +2,13 @@ package tour
 
 import "fmt"
 
-// sections within.
+// returns a partially applied function. 
 //
 // It's designed to make it easy to re-order chapters with minimal fuss.
 //
 // eg.
 // 		Intro := Chapter(1)
-// 		ID("1.1") == Intro(1)
+// 		ID("1.1") == Intro(1) == Chapter(1)(1)
 func Chapter(number int) func(topic int) ID {
 	return func(topic int) ID {
 		return ID(fmt.Sprintf("%d.%d", number, topic))