[docs] Update docwriter stylesheet for 1.3.1.

This change is required to support docwriter 1.3.1.

See

  https://gitlab.freedesktop.org/freetype/docwriter/-/merge_requests/101

for more information.

* docs/markdown/stylesheets/extra.css:
(.wy-nav-content, .md-sidebar--secondary): Remove.
2 files changed