[release-branch.go1.20] crypto/x509: fix ParsePKCS8PrivateKey comment

Updates #58789.
Fixes #58793.

Change-Id: I91cdd20c6d4f05baaacd6a38717aa7bed6682573
Reviewed-on: https://go-review.googlesource.com/c/go/+/472155
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Roland Shoemaker <roland@golang.org>
Auto-Submit: Roland Shoemaker <roland@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
(cherry picked from commit ec26277)
Reviewed-on: https://go-review.googlesource.com/c/go/+/472415
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Bypass: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

src/crypto/x509/pkcs8.go

@@ -28,7 +28,7 @@ type pkcs8 struct {
 // ParsePKCS8PrivateKey parses an unencrypted private key in PKCS #8, ASN.1 DER form.
 //
 // It returns a *rsa.PrivateKey, a *ecdsa.PrivateKey, a ed25519.PrivateKey (not
-// a pointer), or a *ecdh.PublicKey (for X25519). More types might be supported
+// a pointer), or a *ecdh.PrivateKey (for X25519). More types might be supported
 // in the future.
 //
 // This kind of key is commonly encoded in PEM blocks of type "PRIVATE KEY".