How to get the decimal value for a rune in Go?

I need to parse some strings and clean them by parsing any special char as 'â' TO &#226. This is decimal encoding. I know how to parse it to Unicode with this, but I will need the decimal code. The whole idea is to replace those special chars and return the whole string with the conversion if they contain special characters. For example:

text := "chitâra"
text := parseNCRs(text) //can be by reference
parseNCRs(&text) //or passing the pointer
fmt.Println(text) //Outputs: "chitâra"

Range over the string to get the numeric values of the runes.

func escape(s string) string {
  var buf bytes.Buffer
  for _, r := range s {
    if r > 127 {
        fmt.Fprintf(&buf, "&#%d;", r)
    } else {
        buf.WriteRune(r)
    }
  }
  return buf.String()
}

playground

If you are escaping for HTML or XML, then you should also handle other special chracters:

func escape(s string) string {
  var buf bytes.Buffer
  for _, r := range s {
    if r > 127  || r == '<' || r == '>' || r == '&' || r == '"' || r = '\'' {
        fmt.Fprintf(&buf, "&#%d;", r)
    } else {
        buf.WriteRune(r)
    }
  }
  return buf.String()
}