lua unpack -> table.unpack

lua 5.4 apparently fully did away with the former.

Fixes #5546

data/lua/core.lua

@@ -699,7 +699,7 @@ local function reorder_dialog_args(t, n)
 		table.insert( res, t[1])
 		table.remove( t, 1 )
 	end
-	local w = open_dialogs[1]:find(unpack(t))
+	local w = open_dialogs[1]:find(table.unpack(t))
 	return w, res
 end
 
@@ -720,7 +720,7 @@ end
 
 local function set_dialog_canvas(...)
 	local w, args = reorder_dialog_args({...}, 2)
-	w:set_canvas(unpack(args))
+	w:set_canvas(table.unpack(args))
 end
 
 local function set_dialog_focus(...)
@@ -750,12 +750,12 @@ end
 
 local function add_dialog_tree_node(...)
 	local w, args = reorder_dialog_args({...}, 2)
-	w:add_item_of_type(unpack(args))
+	w:add_item_of_type(table.unpack(args))
 end
 
 local function remove_dialog_item(...)
 	local w, args = reorder_dialog_args({...}, 2)
-	w:remove_items_at(unpack(args))
+	w:remove_items_at(table.unpack(args))
 end
 
 local old_show_dialog = gui.show_dialog