adds a limit to the number of markings you can have (30) (#5638)

## About The Pull Request
please don't give yourself 184 markings

## Why It's Good For The Game
please don't give yourself 184 markings

## Changelog
:cl:
add: adds a limit to the number of markings you can have (30)
/:cl:

code/__DEFINES/preferences/misc.dm

@@ -13,3 +13,6 @@
 #define EQUIP_PREVIEW_LOADOUT 1
 #define EQUIP_PREVIEW_JOB 2
 #define EQUIP_PREVIEW_ALL (EQUIP_PREVIEW_LOADOUT|EQUIP_PREVIEW_JOB)
+
+///The maximum number of markings a character can have
+#define MAXIMUM_MARKINGS 30

code/modules/preferences/preference_setup/general/03_body.dm

@@ -571,6 +571,10 @@ var/global/list/valid_bloodtypes = list("A+", "A-", "B+", "B-", "AB+", "AB-", "O
 			var/datum/sprite_accessory/S = GLOB.sprite_accessory_markings[id]
 			translated[S.name] = id
 		var/new_marking = tgui_input_list(user, "Choose a body marking:", "Character Preference", translated)
+		var/marking_count = length(pref.body_marking_ids)
+		if(marking_count >= MAXIMUM_MARKINGS)
+			to_chat(user, "<span class='warning'>You may only select up to [MAXIMUM_MARKINGS] markings!</span>")
+			return
 		if(new_marking && CanUseTopic(user))
 			pref.body_marking_ids[translated[new_marking]] = "#000000" //New markings start black
 			return PREFERENCES_REFRESH_UPDATE_PREVIEW