Remove obsolete TODO comment

lib/reline/line_editor.rb

@@ -241,7 +241,7 @@ class Reline::LineEditor
     @byte_pointer = new_byte_pointer
   end
 
-  def rerender # TODO: support physical and logical lines
+  def rerender
     return if @line.nil?
     if @menu_info
       scroll_down(@highest_in_all - @first_line_started_from)