Change text from

With nested templates, outputs are required to expose any resource
properties of the child templates to the parent template. Those would
not explicitly be declared as parameters but simply referenced as
``get_attribute`` targets against the "parent" resource.

A parameter declared in the outputs: section of a nested template can
be accessed from the parent template as an attribute (i.e., via
``get_attr``) of the "pseudo resource" whose type is in the nested
template. In the case of a ``OS::Heat::ResourceGroup``, an output will be
an attribute of the ``OS::Heat::ResourceGroup`` itself, and will be an
array from the perspective of the parent template.

to

If a VNF's Heat Orchestration Template's nested YAML file is
required to expose a resource property to the invoking Heat Orchestration
Template, an ``outputs:`` statement
must be used in the nested YAML file. The invoking template
references the property by using the intrinsic function ``get_attr``
that targets the resource invoking the nested YAML file and references
the parameter defined in the ``outputs`` section.