internal/reflectlite: fix comment about meaning of flag field

Copied current (presumably correct) comment text from reflect package.

Change-Id: I19582b3675fbcb96a925002498d24ad2b7bc6178
Reviewed-on: https://go-review.googlesource.com/c/go/+/681935
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>

Author: randall77

src/internal/reflectlite/value.go

@@ -43,17 +43,19 @@ type Value struct {
 	ptr unsafe.Pointer
 
 	// flag holds metadata about the value.
-	// The lowest bits are flag bits:
+	//
+	// The lowest five bits give the Kind of the value, mirroring typ.Kind().
+	//
+	// The next set of bits are flag bits:
 	//	- flagStickyRO: obtained via unexported not embedded field, so read-only
 	//	- flagEmbedRO: obtained via unexported embedded field, so read-only
 	//	- flagIndir: val holds a pointer to the data
-	//	- flagAddr: v.CanAddr is true (implies flagIndir)
-	// Value cannot represent method values.
-	// The next five bits give the Kind of the value.
-	// This repeats typ.Kind() except for method values.
-	// The remaining 23+ bits give a method number for method values.
-	// If flag.kind() != Func, code can assume that flagMethod is unset.
+	//	- flagAddr: v.CanAddr is true (implies flagIndir and ptr is non-nil)
+	//	- flagMethod: v is a method value.
 	// If ifaceIndir(typ), code can assume that flagIndir is set.
+	//
+	// The remaining 22+ bits give a method number for method values.
+	// If flag.kind() != Func, code can assume that flagMethod is unset.
 	flag
 
 	// A method value represents a curried method invocation