Replaces /obj:: -> parent_type:: (#81146)

## About The Pull Request

This just seemed like a minor error with the new syntax that popped up:

The intent of these seem to be "take our obj flags and add
`NO_DECONSTRUCTION` to it", which was perfectly serviceable in a
majority of places, as the parent type had the same obj flags as `/obj`.
But in a small handfull of places (such as any table subtypes) this was
not the case, and it caused some objects to have missing flags that they
were otherwise intended(?) to inherit.

So I replaced `/obj::` with `parent_type::` meaning rather than using
the base obj flags and then adding `NO_DECONSTRUCTION`, they use their
parent type's obj flags and then add `NO_DECONSTRUCTION`.

## Changelog

🆑 Melbert
fix: You can build on some niche tables again, such as the Wabbajack
Altar.
/🆑

code/modules/shuttle/spaceship_navigation_beacon.dm

@@ -5,7 +5,7 @@
 	icon_state = "beacon_active"
 	base_icon_state = "beacon"
 	density = TRUE
-	obj_flags = /obj::obj_flags | NO_DECONSTRUCTION
+	obj_flags = parent_type::obj_flags | NO_DECONSTRUCTION
 
 	/// Locked beacons cannot be jumped to by ships.
 	var/locked = FALSE

code/modules/shuttle/special.dm

@@ -79,7 +79,7 @@
 	var/obj/machinery/power/emitter/energycannon/magical/our_statue
 	var/list/mob/living/sleepers = list()
 	var/never_spoken = TRUE
-	obj_flags = /obj::obj_flags | NO_DECONSTRUCTION
+	obj_flags = parent_type::obj_flags | NO_DECONSTRUCTION
 
 /obj/structure/table/abductor/wabbajack/Initialize(mapload)
 	. = ..()
@@ -198,7 +198,7 @@
 
 /obj/structure/table/wood/shuttle_bar
 	resistance_flags = LAVA_PROOF | FIRE_PROOF | ACID_PROOF
-	obj_flags = /obj::obj_flags | NO_DECONSTRUCTION
+	obj_flags = parent_type::obj_flags | NO_DECONSTRUCTION
 	max_integrity = 1000
 	var/boot_dir = 1
 

code/modules/shuttle/syndicate.dm

@@ -11,7 +11,7 @@
 	shuttleId = "syndicate"
 	possible_destinations = "syndicate_away;syndicate_z5;syndicate_ne;syndicate_nw;syndicate_n;syndicate_se;syndicate_sw;syndicate_s;syndicate_custom"
 	resistance_flags = INDESTRUCTIBLE | LAVA_PROOF | FIRE_PROOF | ACID_PROOF
-	obj_flags = /obj::obj_flags | NO_DECONSTRUCTION
+	obj_flags = parent_type::obj_flags | NO_DECONSTRUCTION
 
 /obj/machinery/computer/shuttle/syndicate/launch_check(mob/user)
 	. = ..()