function addSignToFormattedNumber(replacementNumber, formattedReplacement, conversion) {
    if (conversion.signSpecifier === LITERAL_PLUS && replacementNumber >= 0) {
      formattedReplacement = LITERAL_PLUS + formattedReplacement;
    }

    return formattedReplacement;
  }
Add sign to the formatted number.

@ignore
@name addSignToFormattedNumber
@param  {number} replacementNumber The number to be replaced.
@param  {string} formattedReplacement The formatted version of number.
@param  {ConversionSpecification} conversion The conversion specification object.
@return {string} Returns the formatted number string with a sign.