[feat] engines: add NixOS Wiki

Co-authored-by: Bnyro <bnyro@tutanota.com>

searx/settings.yml

@@ -434,6 +434,14 @@ engines:
     engine: archlinux
     shortcut: al
 
+  - name: nixos wiki
+    engine: mediawiki
+    shortcut: nixw
+    base_url: https://wiki.nixos.org/
+    search_type: text
+    disabled: true
+    categories: [it, software wikis]
+
   - name: artic
     engine: artic
     shortcut: arc