iter: fix a tiny doc comment bug

Use the right name for method Pos.Value in a sample doc comment in the package overview. Fixes #76187. Change-Id: Id1f5b0ca4ea39493b10140bc304c57c081c805ee GitHub-Last-Rev: 7bf5d07 GitHub-Pull-Request: #76195 Reviewed-on: https://go-review.googlesource.com/c/go/+/718321 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Alan Donovan <adonovan@google.com> Auto-Submit: Alan Donovan <adonovan@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: bobg

src/iter/iter.go

@@ -188,7 +188,7 @@ For example, a tree implementation might provide:
 // It is only valid during the yield call it is passed to.
 type Pos[V any] struct { ... }
 
-// Pos returns the value at the cursor.
+// Value returns the value at the cursor.
 func (p *Pos[V]) Value() V
 
 // Delete deletes the value at this point in the iteration.