console.lua: update the max width calculation

This should not divide by scale_factor() because osd_w is already scaled
pixels.

Also add a TODO to fix --osd-margin-x's scaling.

player/lua/console.lua

@@ -610,8 +610,10 @@ local function render()
         -- Even with bottom-left anchoring,
         -- libass/ass_render.c:ass_render_event() subtracts --osd-margin-x from
         -- the maximum text width twice.
+        -- TODO: --osd-margin-x should scale with osd-width and PlayResX to make
+        -- the calculation accurate.
         local width_max = math.floor(
-            (osd_w - x - mp.get_property_native('osd-margin-x') * 2 / scale_factor())
+            (osd_w - x - mp.get_property_native('osd-margin-x') * 2)
             / opts.font_size * get_font_hw_ratio())
 
         local completions, rows = format_grid(completion_buffer, width_max, max_lines)