function reserveName(x) {
    var c = x.id.charAt(0);
    if ((c >= "a" && c <= "z") || (c >= "A" && c <= "Z")) {
      x.identifier = x.reserved = true;
    }
    return x;
  }
Denote a given JSHint symbol as an identifier and a reserved keyword.

@param {object} - a JSHint symbol value

@returns {object} - the provided object