Default/nodes: Make water, lava and ice is_ground_content = false

mods/default/nodes.lua

@@ -371,7 +371,7 @@ minetest.register_node("default:snowblock", {
 minetest.register_node("default:ice", {
 	description = "Ice",
 	tiles = {"default_ice.png"},
-	is_ground_content = true,
+	is_ground_content = false,
 	paramtype = "light",
 	groups = {cracky=3},
 	sounds = default.node_sound_glass_defaults(),
@@ -899,6 +899,7 @@ minetest.register_node("default:water_source", {
 	pointable = false,
 	diggable = false,
 	buildable_to = true,
+	is_ground_content = false,
 	drop = "",
 	drowning = 1,
 	liquidtype = "source",
@@ -943,6 +944,7 @@ minetest.register_node("default:water_flowing", {
 	pointable = false,
 	diggable = false,
 	buildable_to = true,
+	is_ground_content = false,
 	drop = "",
 	drowning = 1,
 	liquidtype = "flowing",
@@ -989,6 +991,7 @@ minetest.register_node("default:lava_source", {
 	pointable = false,
 	diggable = false,
 	buildable_to = true,
+	is_ground_content = false,
 	drop = "",
 	drowning = 1,
 	liquidtype = "source",
@@ -1035,6 +1038,7 @@ minetest.register_node("default:lava_flowing", {
 	pointable = false,
 	diggable = false,
 	buildable_to = true,
+	is_ground_content = false,
 	drop = "",
 	drowning = 1,
 	liquidtype = "flowing",