tour: let reader know Walk should send in order

_content/tour/concurrency.article

@@ -113,7 +113,7 @@ Continue description on [[javascript:click('.next-page')][next page]].
 
 * Exercise: Equivalent Binary Trees
 
-*1.* Implement the `Walk` function.
+*1.* Implement the `Walk` function to send all `t` values to `ch` in order.
 
 *2.* Test the `Walk` function.
 

_content/tour/concurrency/exercise-equivalent-binary-trees.go

@@ -4,8 +4,8 @@ package main
 
 import "golang.org/x/tour/tree"
 
-// Walk walks the tree t sending all values
-// from the tree to the channel ch.
+// Walk walks the sorted tree t sending all values
+// in order from the tree to the channel ch.
 func Walk(t *tree.Tree, ch chan int)
 
 // Same determines whether the trees

_content/tour/solutions/binarytrees.go

@@ -21,8 +21,8 @@ func walkImpl(t *tree.Tree, ch chan int) {
 	walkImpl(t.Right, ch)
 }
 
-// Walk walks the tree t sending all values
-// from the tree to the channel ch.
+// Walk walks the sorted tree t sending all values
+// in order from the tree to the channel ch.
 func Walk(t *tree.Tree, ch chan int) {
 	walkImpl(t, ch)
 	// Need to close the channel here

_content/tour/solutions/binarytrees_quit.go

@@ -26,8 +26,8 @@ func walkImpl(t *tree.Tree, ch, quit chan int) {
 	walkImpl(t.Right, ch, quit)
 }
 
-// Walk walks the tree t sending all values
-// from the tree to the channel ch.
+// Walk walks the sorted tree t sending all values
+// in order from the tree to the channel ch.
 func Walk(t *tree.Tree, ch, quit chan int) {
 	walkImpl(t, ch, quit)
 	close(ch)