Release notes do not have headers

As the title.

In the Github release notes, this is the output:

```md
# [0.70.1](https://github.com/ansys/pymapdl/releases/tag/v0.70.1) - May 12, 2025

Added

chore: update version to 0.70.dev0 in pyproject.toml
#3907

chore: update CHANGELOG for v0.70.0
#3913

Fixed

fix: Change the mapdlinprocess graphics
backend
#3915

fix: documentation html looks
#3918

```

Where in the changelog file, we have a very nice formatted table: https://mapdl.docs.pyansys.com/version/stable/changelog.html#may-12-2025

I think we should have headers like:

```md
# [0.70.1](https://github.com/ansys/pymapdl/releases/tag/v0.70.1) - May 12, 2025

## Added

chore: update version to 0.70.dev0 in pyproject.toml
#3907

chore: update CHANGELOG for v0.70.0
#3913

## Fixed

fix: Change the mapdlinprocess graphics
backend
#3915

fix: documentation html looks
#3918

```

Not sure what is the best approach.

Start by locating the reusable workflow or action in this repository that generates GitHub release notes, then compare its output with the linked changelog. Done when sections such as Added and Fixed render as Markdown level-two headers while preserving the existing tables.

Written by the indexing model from the issue text.