remove import comment

x/crypto/pbkdf2/pbkdf2.go

@@ -16,7 +16,7 @@ Hash Functions SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512 for HMAC. To
 choose, you can pass the `New` functions from the different SHA packages to
 pbkdf2.Key.
 */
-package pbkdf2 // import "golang.org/x/crypto/pbkdf2"
+package pbkdf2
 
 import (
 	"crypto/hmac"