crypto/ssh: fix comment for ssh.NewPublicKey

Change-Id: I88bb7859259c82cd77ab2d26b728143281761def
Reviewed-on: https://go-review.googlesource.com/25232
Reviewed-by: Russ Cox <rsc@golang.org>

ssh/keys.go

@@ -722,8 +722,8 @@ func (s *wrappedSigner) Sign(rand io.Reader, data []byte) (*Signature, error) {
 }
 
 // NewPublicKey takes an *rsa.PublicKey, *dsa.PublicKey, *ecdsa.PublicKey,
-// ed25519.PublicKey, or any other crypto.Signer and returns a corresponding
-// Signer instance. ECDSA keys must use P-256, P-384 or P-521.
+// or ed25519.PublicKey returns a corresponding PublicKey instance.
+// ECDSA keys must use P-256, P-384 or P-521.
 func NewPublicKey(key interface{}) (PublicKey, error) {
 	switch key := key.(type) {
 	case *rsa.PublicKey: