_setTrailingNegativeSignInfo() {
        this.isTrailingNegative = (this.settings.currencySymbolPlacement === AutoNumeric.options.currencySymbolPlacement.prefix && this.settings.negativePositiveSignPlacement === AutoNumeric.options.negativePositiveSignPlacement.suffix) ||
        (this.settings.currencySymbolPlacement === AutoNumeric.options.currencySymbolPlacement.suffix &&
        (this.settings.negativePositiveSignPlacement === AutoNumeric.options.negativePositiveSignPlacement.left || this.settings.negativePositiveSignPlacement === AutoNumeric.options.negativePositiveSignPlacement.right));
    }
Keep track if the settings configuration leads to a trailing negative sign (only when the raw value is negative), so we do not have to test the settings values every time we need to know that.
`isTrailingNegative` is set to `true` if the settings result in a trailing negative character, `false` otherwise.
Note: This returns `true` even if the raw value is positive.
@private