Fix comment

utils.go

@@ -200,7 +200,7 @@ func (d *Deferred) UnmarshalCBOR(br io.Reader) error {
 	return nil
 }
 
-// readByte returns the first byte from the reader or ErrUnexpectedEOF if no byte is available.
+// readByte reads and returns the next byte from the buffer. If no byte is available, it returns error io.EOF.
 func readByte(r io.Reader) (byte, error) {
 	// try to cast to a concrete type, it's much faster than casting to an
 	// interface.