reflect: clarify documentation for Value.Seq/Seq2

For #66056

Change-Id: Ib47c07b2527d8213584b72e2575a353f2deaed68
GitHub-Last-Rev: 525a5c3
GitHub-Pull-Request: #67268
Reviewed-on: https://go-review.googlesource.com/c/go/+/584515
Reviewed-by: Cherry Mui <cherryyz@google.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

src/reflect/iter.go

@@ -6,7 +6,7 @@ package reflect
 
 import "iter"
 
-// Seq returns an iter.Seq[reflect.Value] that loops over the elements of v.
+// Seq returns an iter.Seq[Value] that loops over the elements of v.
 // If v's kind is Func, it must be a function that has no results and
 // that takes a single argument of type func(T) bool for some type T.
 // If v's kind is Pointer, the pointer element type must have kind Array.
@@ -87,7 +87,11 @@ func (v Value) Seq() iter.Seq[Value] {
 	panic("reflect: " + v.Type().String() + " cannot produce iter.Seq[Value]")
 }
 
-// Seq2 is like Seq but for two values.
+// Seq2 returns an iter.Seq2[Value, Value] that loops over the elements of v.
+// If v's kind is Func, it must be a function that has no results and
+// that takes a single argument of type func(K, V) bool for some type K, V.
+// If v's kind is Pointer, the pointer element type must have kind Array.
+// Otherwise v's kind must be Array, Map, Slice, or String.
 func (v Value) Seq2() iter.Seq2[Value, Value] {
 	if canRangeFunc2(v.typ()) {
 		return func(yield func(Value, Value) bool) {