Update products.mdx with price method. Related to PR in Lunar Core, (#15)

Added additional example for Tax Incl Price based on PR: lunarphp/lunar#2406

Author: MacTavish-69

1.x/reference/products.mdx

@@ -663,8 +663,10 @@ available on the `Lunar\Models\Price` model.
 
 ```php
 $price->priceIncTax();
+$price->priceIncTax($yourTaxZone); // TaxIncl Price based on your Tax Zone and Tax Rate.
 $price->priceExTax();
 $price->comparePriceIncTax(); // to retrieve the tax inclusive compare price
+$price->comparePriceIncTax($yourTaxZone); // TaxIncl Price based on your Tax Zone and Tax Rate.
 ```
 
 ### Customising Prices with Pipelines