Splitting template integration config

Configuration
1

I’m trying to split my sensor templates configuration, but when I move working templates to a separate file it no longer works.

I know there are ways to merge directories etc. But I would like this simple way to work.
It’s documented on Splitting up the configuration - Home Assistant (search for multiple top-level).

Why does this work:

configuration.yaml

template:
  - binary_sensor:
      - name: "Living Room HVAC Off"
        state: >
          {{ is_state('climate.living_room_hvac_2', 'off') }}
  - sensor:
      - name: Heating Living Room
        state: >
          {{ state_attr('climate.living_room', 'temperature') }}
        icon: >
          {% if is_state_attr('climate.living_room', 'hvac_action', 'heating') %}
            mdi:radiator
          {% else %}
            mdi:radiator-disabled
          {% endif %}

But this doesn’t:

configuration.yaml

template:
  - binary_sensor:
      - name: "Living Room HVAC Off"
        state: >
          {{ is_state('climate.living_room_hvac_2', 'off') }}
template heating: !include heating.yaml

heating.yaml

- sensor:
  - name: Heating Living Room
    state: >
      {{ state_attr('climate.living_room', 'temperature') }}
    icon: >
      {% if is_state_attr('climate.living_room', 'hvac_action', 'heating') %}
        mdi:radiator
      {% else %}
        mdi:radiator-disabled
      {% endif %}

I’m not getting any errors. The sensor just does not show up…

Thanks.