all: fix a few function names on comments

Change-Id: Iac9c8f06b874e62b56f634dede8757b87514f421
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/442135
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Joedian Reid <joedian@golang.org>

openpgp/s2k/s2k.go

@@ -268,7 +268,7 @@ func HashIdToString(id byte) (name string, ok bool) {
 	return "", false
 }
 
-// HashIdToHash returns an OpenPGP hash id which corresponds the given Hash.
+// HashToHashId returns an OpenPGP hash id which corresponds the given Hash.
 func HashToHashId(h crypto.Hash) (id byte, ok bool) {
 	for _, m := range hashToHashIdMapping {
 		if m.hash == h {