Update Saint Martin country names

dropstream/app_issues#1021 (comment)

It appears that between 2023 and 2024 API versions, NetSuite has changed from
_sintMaarten & _saintMartin to _sintMaartenDutchPart  and _saintMartinFrenchPart .

https://netsuite.com/help/helpcenter/en_US/srbrowser/Browser2023_1/schema/enum/country.html?mode=package
https://netsuite.com/help/helpcenter/en_US/srbrowser/Browser2024_1/schema/enum/country.html?mode=package

lib/netsuite/support/country.rb

@@ -195,7 +195,7 @@ class Country
         'SH' => '_saintHelena',
         'KN' => '_saintKittsAndNevis',
         'LC' => '_saintLucia',
-        'MF' => '_saintMartin',
+        'MF' => '_saintMartinFrenchPart',
         'VC' => '_saintVincentAndTheGrenadines',
         'SM' => '_sanMarino',
         'ST' => '_saoTomeAndPrincipe',
@@ -205,7 +205,7 @@ class Country
         'SC' => '_seychelles',
         'SL' => '_sierraLeone',
         'SG' => '_singapore',
-        'SX' => '_sintMaarten',
+        'SX' => '_sintMaartenDutchPart',
         'SK' => '_slovakRepublic',
         'SI' => '_slovenia',
         'SB' => '_solomonIslands',