Adds USCM Poncho To Synth Vendor (#3687)

# About the pull request

Adds the USCM Poncho as a purchase option to the Synthetic snowflake
vendor.

# Explain why it's good for the game

More ability to customize your shipboard Synthetic is a good thing I
believe.


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

![Screenshot 2023-06-21 19 18
53](https://github.com/cmss13-devs/cmss13/assets/6595389/1f07a8b0-197d-43e3-9603-9f3dcd052170)


</details>


# Changelog
:cl:
add: Synthetics may now vend Ponchos. 
/:cl:

Co-authored-by: Steelpoint <[email protected]>

code/game/machinery/vending/vendor_types/crew/synthetic.dm

@@ -244,6 +244,7 @@ GLOBAL_LIST_INIT(cm_vending_clothing_synth_snowflake, list(
 	list("Labcoat", 12, /obj/item/clothing/suit/storage/labcoat, null, VENDOR_ITEM_REGULAR),
 	list("Labcoat, Researcher", 12, /obj/item/clothing/suit/storage/labcoat/researcher, null, VENDOR_ITEM_REGULAR),
 	list("RO Jacket", 12, /obj/item/clothing/suit/storage/RO, null, VENDOR_ITEM_REGULAR),
+	list("USCM Poncho", 12, /obj/item/clothing/accessory/poncho, null, VENDOR_ITEM_REGULAR),
 
 	list("BACKPACK", 0, null, null, null),
 	list("Backpack, Industrial", 12, /obj/item/storage/backpack/industrial, null, VENDOR_ITEM_REGULAR),