Tweaks railings to stand and look taller [MDB IGNORE] (#24070)

* Tweaks railings to stand and look taller (#78598)

## About The Pull Request

![image](https://github.com/tgstation/tgstation/assets/41715314/e905463f-6b83-4ff2-b265-7029d542301a)

This Pull request updates the sprites used by railings, including both
directional, corner, outer corner, and rail ending sprites.
Additionally, I've placed railings on the GAME_PLANE_UPPER plane, so
that visually it looks like railings in front of a player can physically
stand in front of the player.

## Why It's Good For The Game

This ports the railing sprites I did for The Wallening (tm) onto live,
providing a 3/4ths perspective sprite, in addition to the fact that
it'll help sell the height of objects by layering in a more satisfying
way.

Not to mention, I just think they're way better than current railings,
where are both ancient and super flat sprites.

## Changelog

:cl:
image: Railings have had a visual update.
/:cl:

* Tweaks railings to stand and look taller

---------

Co-authored-by: ArcaneMusic <[email protected]>

code/game/objects/structures/railings.dm

@@ -8,6 +8,8 @@
 	density = TRUE
 	anchored = TRUE
 	pass_flags_self = LETPASSTHROW|PASSSTRUCTURE
+	layer = ABOVE_MOB_LAYER
+	plane = GAME_PLANE_UPPER
 	/// armor is a little bit less than a grille. max_integrity about half that of a grille.
 	armor_type = /datum/armor/structure_railing
 	max_integrity = 25