[MIRROR] Fixes security level alerts playing the incorrect sounds [MDB IGNORE] (#15116)

* Fixes security level alerts playing the incorrect sounds

* Fixes the merge conflict

* Slightly improves the code on our end, adds the documentation that we were now missing

Co-authored-by: MrMelbert <51863163+MrMelbert@users.noreply.github.com>
Co-authored-by: GoldenAlpharex <jerego1234@hotmail.com>

code/modules/security_levels/security_level_datums.dm

@@ -42,6 +42,7 @@
  */
 /datum/security_level/green
 	name = "green"
+	sound = 'sound/misc/notice2.ogg' // Friendly beep
 	number_level = SEC_LEVEL_GREEN
 	lowering_to_configuration_key = /datum/config_entry/string/alert_green
 	shuttle_call_time_mod = 2
@@ -53,6 +54,7 @@
  */
 /datum/security_level/blue
 	name = "blue"
+	sound = 'sound/misc/notice1.ogg' // Angry alarm
 	number_level = SEC_LEVEL_BLUE
 	lowering_to_configuration_key = /datum/config_entry/string/alert_blue_downto
 	elevating_to_configuration_key = /datum/config_entry/string/alert_blue_upto
@@ -65,6 +67,7 @@
  */
 /datum/security_level/red
 	name = "red"
+	sound = 'sound/misc/notice1.ogg' // The same angry alarm
 	number_level = SEC_LEVEL_RED
 	lowering_to_configuration_key = /datum/config_entry/string/alert_red_downto
 	elevating_to_configuration_key = /datum/config_entry/string/alert_red_upto
@@ -77,6 +80,7 @@
  */
 /datum/security_level/delta
 	name = "delta"
+	sound = 'sound/misc/notice1.ogg' // The same angry alarm, again
 	number_level = SEC_LEVEL_DELTA
 	elevating_to_configuration_key = /datum/config_entry/string/alert_delta
 	shuttle_call_time_mod = 0.25