Draft: enable search bar when updating mkdocs-material to ver 9.x
requested to merge draft-solution-to-disappearing-searchbar-for-update-to-mkdocs-material-9.x into preview
changed line 72 in ./doc.zih.tu-dresden.de/tud_theme/partials/header.html
from
{% if "search" in config["plugins"] %}
to
{% if "material/search" in config["plugins"] %}
solution is described here:
https://squidfunk.github.io/mkdocs-material/upgrade/#changes-to-html-files
and
https://github.com/squidfunk/mkdocs-material/issues/4581