use minetest.rotate_node to place slopes

(6dfacedir prediction)

homedecor/slopes.lua

@@ -47,6 +47,7 @@ homedecor.register_outer_corner = function(modname, subname, groups, slope_image
 		selection_box = ocorner_cbox,
 		collision_box = ocorner_cbox,
 		groups = groups,
+		on_place = minetest.rotate_node
 	})
 end
 
@@ -65,6 +66,7 @@ homedecor.register_inner_corner = function(modname, subname, groups, slope_image
 		},
 		collision_box = icorner_cbox,
 		groups = groups,
+		on_place = minetest.rotate_node
 	})
 end
 
@@ -80,6 +82,7 @@ homedecor.register_slope = function(modname, subname, recipeitem, groups, slope_
 		selection_box = slope_cbox,
 		collision_box = slope_cbox,
 		groups = groups,
+		on_place = minetest.rotate_node
 	})
 
 	-- convert between flat shingles and slopes