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

graphics/elements/rectangle.lua

@@ -16,6 +16,7 @@ local element = require("graphics.element")
 ---@field height? integer parent height if omitted
 ---@field gframe? graphics_frame frame instead of x/y/width/height
 ---@field fg_bg? cpair foreground/background colors
+---@field hidden? boolean true to hide on initial draw
 
 -- new rectangle
 ---@param args rectangle_args