Update chain -> icon_chain

Author: misode

base/data/gm4/tags/block/waterloggable.json

@@ -20,7 +20,8 @@
     "minecraft:blue_stained_glass_pane",
     "minecraft:brown_stained_glass_pane",
     "minecraft:calibrated_sculk_sensor",
-    "minecraft:chain",
+    { "id": "minecraft:chain", "required": false },
+    { "id": "minecraft:iron_chain", "required": false },
     "minecraft:chest",
     "minecraft:conduit",
     "minecraft:cyan_stained_glass_pane",

gm4_tunnel_bores/data/gm4_tunnel_bores/tags/block/not_rail_solid.json

@@ -143,7 +143,8 @@
     "minecraft:crimson_roots",
     "minecraft:warped_roots",
     "minecraft:nether_sprouts",
-    "minecraft:chain",
+    { "id": "minecraft:chain", "required": false },
+    { "id": "minecraft:iron_chain", "required": false },
     "minecraft:warped_fence",
     "minecraft:crimson_fence_gate",
     "minecraft:sweet_berry_bush",