Add code comment about mcc

src/forms/PayoutDetailsForm/PayoutDetailsBusinessProfile.js

@@ -28,6 +28,10 @@ const PayoutDetailsBusinessProfile = props => {
     intl.formatMessage({ id: 'PayoutDetailsForm.businessURLRequired' })
   );
 
+  // By default, all merchant category codes (MCC) are listed in the select field. You can edit the
+  // merchantCategoryCodesUS.js and remove the codes that are not relevant to your marketplace or use a hard-coded
+  // value if there is only one code you want to use.
+
   return isBusinessProfileNeeded ? (
     <React.Fragment>
       {showMCCForUSField ? (