Adds time defines to a couple of shooting related delay vars (#93966)

## About The Pull Request

Converted `fire_delay` and `shot_delay` vars to use time defines

## Why It's Good For The Game

Code readability

## Changelog
🆑
code: Converted some gun related variables to use time defines, make an
issue report if anything shoots abnormally fast/slow.
/🆑

code/modules/projectiles/gun.dm

@@ -47,7 +47,7 @@
 	/// Delay between shots in a burst.
 	var/burst_delay = 2
 	/// Delay between bursts (if burst-firing) or individual shots (if weapon is single-fire).
-	var/fire_delay = 0
+	var/fire_delay = 0 SECONDS
 	var/firing_burst = 0 //Prevent the weapon from firing again while already firing
 	/// firing cooldown, true if this gun shouldn't be allowed to manually fire
 	var/fire_cd = 0

code/modules/projectiles/guns/ballistic.dm

@@ -286,7 +286,7 @@
 	burst_fire_selection = !burst_fire_selection
 	if(!burst_fire_selection)
 		burst_size = 1
-		fire_delay = 0
+		fire_delay = 0 SECONDS
 		balloon_alert(user, "switched to semi-automatic")
 	else
 		burst_size = initial(burst_size)

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

@@ -330,7 +330,7 @@
 	accepted_magazine_type = /obj/item/ammo_box/magazine/recharge
 	empty_indicator = TRUE
 	bolt_type = BOLT_TYPE_OPEN
-	fire_delay = 2
+	fire_delay = 2 DECISECONDS
 	can_suppress = FALSE
 	burst_size = 0
 	actions_types = list()
@@ -359,7 +359,7 @@
 	mag_display = TRUE
 	projectile_damage_multiplier = 1.2
 	projectile_speed_multiplier = 1.2
-	fire_delay = 2
+	fire_delay = 2 DECISECONDS
 	burst_size = 1
 	actions_types = list()
 	fire_sound = 'sound/items/weapons/thermalpistol.ogg'

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

@@ -60,7 +60,7 @@
 	fire_sound = 'sound/items/weapons/gun/general/grenade_launch.ogg'
 	accepted_magazine_type = /obj/item/ammo_box/magazine/m75
 	burst_size = 1
-	fire_delay = 0
+	fire_delay = 0 SECONDS
 	actions_types = list()
 	casing_ejector = FALSE
 
@@ -82,7 +82,7 @@
 	can_suppress = FALSE
 	pin = /obj/item/firing_pin/implant/pindicate
 	burst_size = 1
-	fire_delay = 0
+	fire_delay = 0 SECONDS
 	casing_ejector = FALSE
 	weapon_weight = WEAPON_HEAVY
 	bolt_type = BOLT_TYPE_NO_BOLT

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

@@ -6,7 +6,7 @@
 	accepted_magazine_type = /obj/item/ammo_box/magazine/m9mm
 	can_suppress = TRUE
 	burst_size = 1
-	fire_delay = 0
+	fire_delay = 0 SECONDS
 	actions_types = list()
 	bolt_type = BOLT_TYPE_LOCKING
 	fire_sound = 'sound/items/weapons/gun/pistol/shot.ogg'

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

@@ -46,7 +46,7 @@
 	desc = "A sturdy shotgun with a longer magazine and a fixed tactical stock designed for non-lethal riot control."
 	icon_state = "riotshotgun"
 	inhand_icon_state = "shotgun"
-	fire_delay = 8
+	fire_delay = 8 DECISECONDS
 	accepted_magazine_type = /obj/item/ammo_box/magazine/internal/shot/riot
 	sawn_desc = "Come with me if you want to live."
 	can_be_sawn_off = TRUE