Fixes an issue with SUNS outfits (#2706)

<!-- Write **BELOW** The Headers and **ABOVE** The comments else it may
not be viewable. -->
<!-- You can view Contributing.MD for a detailed description of the pull
request process. -->

## About The Pull Request
Title, the SUNS graduate outfit did not have the alt jumpsuit set to the
alt jumpsuit
<!-- Describe The Pull Request. Please be sure every change is
documented or this can delay review and even discourage maintainers from
merging your PR! -->

## Why It's Good For The Game
Outfits working properly is good
<!-- Please add a short description of why you think these changes would
benefit the game. If you can't justify it in words, it might not be
worth adding. -->

## Changelog

:cl:
fix: Fixed a minor issue with SUNS outfits
/🆑

<!-- Both :cl:'s are required for the changelog to work! You can put
your name to the right of the first :cl: if you want to overwrite your
GitHub username as author ingame. -->
<!-- You can use multiple of the same prefix (they're only used for the
icon ingame) and delete the unneeded ones. Despite some of the tags,
changelogs should generally represent how a player might be affected by
the changes rather than a summary of the PR's contents. -->

code/modules/clothing/outfits/factions/syndicate.dm

@@ -126,7 +126,7 @@
 	name = "Syndicate - Graduate (SUNS)"
 
 	uniform = /obj/item/clothing/under/syndicate/suns/uniform3
-	alt_uniform = /obj/item/clothing/under/syndicate/suns/uniform3
+	alt_uniform = /obj/item/clothing/under/syndicate/suns/uniform3/alt
 
 //atmos techs