More map lints (Monkestation#1860)

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## About The Pull Request
Add lint for stairs on closed turfs and openspace AND FIX

Add lint for turf icon varedits AND FIX

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## Why It's Good For The Game
Less map issue = good

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- [ ] You tested this on a local server.
- [ ] This code did not runtime during testing.
- [x] You documented all of your changes.
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Author: CheffieGithub

_maps/map_files/daftmarsh/daftmarsh.dmm

@@ -29,10 +29,6 @@
 /obj/structure/flora/newtree/snow,
 /turf/open/floor/grass,
 /area/rogue/outdoors/rtfield)
-"aC" = (
-/obj/structure/stairs/stone,
-/turf/open/transparent/openspace,
-/area/rogue/under/mountains/anvil/lower)
 "aE" = (
 /obj/structure/chair/wood/alt{
 	dir = 8
@@ -1030,9 +1026,7 @@
 	},
 /obj/effect/mapping_helpers/access/locker,
 /obj/effect/mapping_helpers/access/keyset/garrison/forest,
-/turf/open/floor/metal{
-	icon_state = "plating2"
-	},
+/turf/open/floor/metal/alt,
 /area/rogue/indoors/town/cell)
 "kf" = (
 /obj/machinery/light/fueled/campfire/densefire,
@@ -1132,9 +1126,7 @@
 	},
 /obj/effect/mapping_helpers/access/locker,
 /obj/effect/mapping_helpers/access/keyset/garrison/forest,
-/turf/open/floor/metal{
-	icon_state = "plating2"
-	},
+/turf/open/floor/metal/alt,
 /area/rogue/indoors/town/cell)
 "li" = (
 /obj/structure/rack,
@@ -1766,7 +1758,7 @@
 /obj/structure/stairs/stone{
 	dir = 8
 	},
-/turf/open/transparent/openspace,
+/turf/open/floor/herringbone,
 /area/rogue/under/mountains/anvil/lower)
 "su" = (
 /obj/item/chair,
@@ -2767,7 +2759,7 @@
 /obj/structure/stairs/stone{
 	dir = 4
 	},
-/turf/open/transparent/openspace,
+/turf/open/floor/herringbone,
 /area/rogue/under/mountains/anvil/lower)
 "DR" = (
 /obj/structure/table/wood/plain_alt,
@@ -46435,7 +46427,7 @@ bv
 PF
 PF
 PF
-aC
+Mn
 GX
 GX
 GX
@@ -46637,7 +46629,7 @@ bv
 PF
 PF
 PF
-aC
+Mn
 GX
 kc
 GX