crypto/x509: fix typo in godoc for ParseECPrivateKey

Change-Id: Ia65bac00fe8600f50620ce0583455eb33f06ff95
Reviewed-on: https://go-review.googlesource.com/c/go/+/207918
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>

src/crypto/x509/sec1.go

@@ -28,9 +28,9 @@ type ecPrivateKey struct {
 	PublicKey     asn1.BitString        `asn1:"optional,explicit,tag:1"`
 }
 
-// ParseECPrivateKey parses an EC public key in SEC 1, ASN.1 DER form.
+// ParseECPrivateKey parses an EC private key in SEC 1, ASN.1 DER form.
 //
-// This kind of key is commonly encoded in PEM blocks of type "EC PUBLIC KEY".
+// This kind of key is commonly encoded in PEM blocks of type "EC PRIVATE KEY".
 func ParseECPrivateKey(der []byte) (*ecdsa.PrivateKey, error) {
 	return parseECPrivateKey(nil, der)
 }