This Fixes#3962 by adding `!important` to the margin of the heading in the rendered markdown.
In the current behaviour, the margin-top was always overridden by a global css-rule. This is prevented by this change.
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/4076
Reviewed-by: 0ko <0ko@noreply.codeberg.org>
Co-authored-by: Beowulf <beowulf@beocode.eu>
Co-committed-by: Beowulf <beowulf@beocode.eu>
(cherry picked from commit 187860bded)
