Top line is applied twice

[kasium]

Hi,
with the latest version of towncrier the top line is twice applied leading to a weird text and invalid rST.

pyproject.toml

[tool.towncrier]
filename = "CHANGELOG.rst"
directory = "news/"
title_format = "{version} ({project_date})"

  [[tool.towncrier.type]]
  directory = "feature"
  name = "Features"
  showcontent = true

news/123.feature

dummy

CHANGELOG.rst

.. towncrier release notes start

If I now execute towncrier --yes --version 0.50.0, teh following text is generated:

CHANGELOG.rst

0.50.0 (2021-06-28)0.50.0 (2021-06-28)
===================

Features
--------

- dummy (#1234)


.. towncrier release notes start

[pquentin]

Can confirm the bug when a title_format is specified

[pquentin]

This is a duplicate of #346 though.

[kasium]

Thanks, I'll close it