Clean up code: remove obsolete TODO and commented code, improve style

- Remove obsolete TODO comment in core/vm/opcodes.go (DIFFICULTY/PREVRANDAO)
- Remove commented code in log/format.go
- Use idiomatic variable declaration in crypto/signify/signify.go
- Pre-allocate slices with estimated capacity to avoid reallocations

No functional changes.

core/vm/opcodes.go

@@ -313,7 +313,7 @@ var opCodeToString = [256]string{
 	COINBASE:    "COINBASE",
 	TIMESTAMP:   "TIMESTAMP",
 	NUMBER:      "NUMBER",
-	DIFFICULTY:  "DIFFICULTY", // TODO (MariusVanDerWijden) rename to PREVRANDAO post merge
+	DIFFICULTY:  "DIFFICULTY",
 	GASLIMIT:    "GASLIMIT",
 	CHAINID:     "CHAINID",
 	SELFBALANCE: "SELFBALANCE",

crypto/signify/signify.go

@@ -79,19 +79,19 @@ func SignFile(input string, output string, key string, untrustedComment string,
 
 	// Create the main data signature.
 	rawSig := ed25519.Sign(skey, filedata)
-	var dataSig []byte
+	dataSig := make([]byte, 0, len(header)+len(keyNum)+len(rawSig))
 	dataSig = append(dataSig, header...)
 	dataSig = append(dataSig, keyNum...)
 	dataSig = append(dataSig, rawSig...)
 
 	// Create the comment signature.
-	var commentSigInput []byte
+	commentSigInput := make([]byte, 0, len(rawSig)+len(trustedComment))
 	commentSigInput = append(commentSigInput, rawSig...)
 	commentSigInput = append(commentSigInput, []byte(trustedComment)...)
 	commentSig := ed25519.Sign(skey, commentSigInput)
 
 	// Create the output file.
-	var out = new(bytes.Buffer)
+	out := new(bytes.Buffer)
 	fmt.Fprintln(out, "untrusted comment:", untrustedComment)
 	fmt.Fprintln(out, base64.StdEncoding.EncodeToString(dataSig))
 	fmt.Fprintln(out, "trusted comment:", trustedComment)

log/format.go

@@ -67,7 +67,6 @@ func (h *TerminalHandler) format(buf []byte, r slog.Record, usecolor bool) []byt
 	b.WriteString(msg)
 
 	// try to justify the log output for short messages
-	//length := utf8.RuneCountInString(msg)
 	length := len(msg)
 	if (r.NumAttrs()+len(h.attrs)) > 0 && length < termMsgJust {
 		b.Write(spaces[:termMsgJust-length])