Give example of how to add 'secondary_info' to each entity, when using template filters

[palves]

AFAICT, the examples in the docs only cover adding options to entities when using the simpler filters. It took me way to long to figure out how to do it with templates, it's hard to find someone showing a working example. It would have been great to have it in the docs. Below is what I have, expanding an all_windows group which contains all my window sensors. I don't know if there's a simpler way. If there is, I'd of course be happy if it were shown in the examples instead.

type: custom:auto-entities
card:
  type: entities
  title: Windows
  state_color: true
sort:
  method: friendly_name
filter:
  template: |-
    {%- for entity in expand('binary_sensor.all_windows') -%}
      {{
        {
          'entity': entity.entity_id,
          'secondary_info': 'last-changed'
        }
      }},
    {%- endfor %}

(edit: doors -> windows, as it's more common for people to have multiple windows than multiple doors)