* This was missed during the migration to Jinja 3.
* In Jinja 2.10, the parameter 'indentfirst' of function do_indent()
  was marked deprecated and a functionally identical 'first' was added.
* In Jinja 3.0, the deprecated functionality was removed, in this
  upstream commit:
  https://github.com/pallets/jinja/commit/b0015c72d5acbf93b9d99a1ce6167889338db85b

(Redmine issue: #7583)