graphics element hidden on creation option, changed hide/show logic to only hide/show current element

graphics/elements/colormap.lua

@@ -9,6 +9,7 @@ local element = require("graphics.element")
 ---@field id? string element id
 ---@field x? integer 1 if omitted
 ---@field y? integer 1 if omitted
+---@field hidden? boolean true to hide on initial draw
 
 -- new color map
 ---@param args colormap_args