go/callgraph: change reflect.Call to reflect.Value.Call in comment

Change-Id: I672a2dcd5a50c6d6cb5bbe2c0d0c53ff56d24efd
Reviewed-on: https://go-review.googlesource.com/c/tools/+/331709
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
diff --git a/go/callgraph/callgraph.go b/go/callgraph/callgraph.go
index 707a319..2bcc3dc 100644
--- a/go/callgraph/callgraph.go
+++ b/go/callgraph/callgraph.go
@@ -89,7 +89,7 @@
 // A Edge represents an edge in the call graph.
 //
 // Site is nil for edges originating in synthetic or intrinsic
-// functions, e.g. reflect.Call or the root of the call graph.
+// functions, e.g. reflect.Value.Call or the root of the call graph.
 type Edge struct {
 	Caller *Node
 	Site   ssa.CallInstruction