Revert "Add Chicken-Libraries to Users.md (#8180)"

This reverts commit 72365e6856.

This is a vanity project that no longer exists.

See discussion at #8890, which still requires further thought but we can
at least start off by removing something clearly invalid.

docs/markdown/Users.md

@@ -23,7 +23,6 @@ topic](https://github.com/topics/meson).
  - [Cage](https://github.com/Hjdskes/cage), a Wayland kiosk
  - [canfigger](https://github.com/andy5995/canfigger), simple configuration file parser library
  - [casync](https://github.com/systemd/casync), Content-Addressable Data Synchronization Tool
- - [Chicken Libraries](https://github.com/chicken-libraries), Collection of C libraries. Data structures, algorithms, and more.
  - [cinnamon-desktop](https://github.com/linuxmint/cinnamon-desktop), the cinnamon desktop library
  - [Cozy](https://github.com/geigi/cozy), a modern audio book player for Linux and macOS using GTK+ 3
  - [dav1d](https://code.videolan.org/videolan/dav1d), an AV1 decoder