add a __tostring method to every object (#1534)

* added a stupid __tostring to every object

* moved every __tostring to just after the :extend() call

---------

Co-authored-by: Adam <adamdharrison@gmail.com>
(cherry picked from commit 880e7f1fa1521cdf176f44627a27c901e187058e)

data/core/contextmenu.lua

@@ -33,6 +33,8 @@ local DIVIDER = {}
 ---@field current_scale number
 local ContextMenu = Object:extend()
 
+function ContextMenu:__tostring() return "ContextMenu" end
+
 ---A unique value representing the divider in a context menu.
 ContextMenu.DIVIDER = DIVIDER