Brown Gloves/Boots Surplus Vendors (#4996)

# About the pull request

adds brown gloves and boots to the surplus vendors

# Explain why it's good for the game

It's a drip or drown world out there, and our marines need a life-vests.


# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>


![image](https://github.com/cmss13-devs/cmss13/assets/91508746/10ce0430-8e18-4e35-8244-7fafe5e30b37)

</details>


# Changelog
:cl:
add: Brown boots and gloves are now vendable from the surplus vendors.
/:cl:

code/game/machinery/vending/vendor_types/squad_prep/squad_prep.dm

@@ -71,8 +71,10 @@
 	listed_products = list(
 		list("STANDARD EQUIPMENT", -1, null, null, null),
 		list("Marine Combat Boots", round(scale * 15), /obj/item/clothing/shoes/marine, VENDOR_ITEM_REGULAR),
+		list("Marine Brown Combat Boots", round(scale * 15), /obj/item/clothing/shoes/marine/brown, VENDOR_ITEM_REGULAR),
 		list("USCM Uniform", round(scale * 15), /obj/item/clothing/under/marine, VENDOR_ITEM_REGULAR),
 		list("Marine Combat Gloves", round(scale * 15), /obj/item/clothing/gloves/marine, VENDOR_ITEM_REGULAR),
+		list("Marine Brown Combat Gloves", round(scale * 15), /obj/item/clothing/gloves/marine/brown, VENDOR_ITEM_REGULAR),
 		list("Marine Black Combat Gloves", round(scale * 15), /obj/item/clothing/gloves/marine/black, VENDOR_ITEM_REGULAR),
 		list("Marine Radio Headset", round(scale * 15), /obj/item/device/radio/headset/almayer, VENDOR_ITEM_REGULAR),
 		list("M10 Pattern Marine Helmet", round(scale * 15), /obj/item/clothing/head/helmet/marine, VENDOR_ITEM_REGULAR),