Claris and Gar Can Now Be Stored On Your Back (#3852)

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## About The Pull Request
The Claris and Gar can now be stored on your back, and suit storage (if
you have armour)

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## Why It's Good For The Game
It was massively inconsistent that every other large rifle can be stored
on the back slot.
Also Solarians are the kind of mf'ers to sacrifice their bag to look
more 'proper'.
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## Changelog

:cl:
fix: Claris and Gar can now be stored on your back
/:cl:

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code/modules/projectiles/guns/ballistic/gauss.dm

@@ -103,6 +103,7 @@
 	allowed_cell_types = list(
 		/obj/item/stock_parts/cell/gun/solgov,
 	)
+	slot_flags = ITEM_SLOT_BACK
 	fire_delay = 0.4 SECONDS
 	bolt_type = BOLT_TYPE_NO_BOLT
 	internal_magazine = TRUE
@@ -143,8 +144,8 @@
 	allowed_cell_types = list(
 		/obj/item/stock_parts/cell/gun/solgov,
 	)
+	slot_flags = ITEM_SLOT_BACK
 	burst_size = 1
-
 	fire_delay = 0.2 SECONDS
 
 	actions_types = list()