rm: Wiki Engine Ref - Dead link

README.md

@@ -2086,7 +2086,7 @@ A [wiki](https://en.wikipedia.org/wiki/Wiki) is a publication collaboratively ed
 
 _Related: [Static Site Generators](#static-site-generators)_
 
-_See also: [Wikimatrix](https://www.wikimatrix.org/), [Wiki Engines - WikiIndex](https://wikiindex.org/Category:Wiki_Engine), [List of wiki software - Wikipedia](https://en.wikipedia.org/wiki/List_of_wiki_software), [Comparison of wiki software - Wikipedia](https://en.wikipedia.org/wiki/Comparison_of_wiki_software)_
+_See also: [Wikimatrix](https://www.wikimatrix.org/), [List of wiki software - Wikipedia](https://en.wikipedia.org/wiki/List_of_wiki_software), [Comparison of wiki software - Wikipedia](https://en.wikipedia.org/wiki/Comparison_of_wiki_software)_
 
 - [AmuseWiki](https://amusewiki.org/) - Amusewiki is based on the Emacs Muse markup, remaining mostly compatible with the original implementation. It can work as a read-only site, as a moderated wiki, or as a fully open wiki or even as a private site. ([Demo](https://sandbox.amusewiki.org), [Source Code](https://github.com/melmothx/amusewiki)) `GPL-1.0` `Perl/Docker`
 - [BookStack](https://www.bookstackapp.com/) - BookStack is a simple, self-hosted, easy-to-use platform for organizing and storing information. It allows for documentation to be stored in a book like fashion. ([Demo](https://www.bookstackapp.com/#demo), [Source Code](https://github.com/BookStackApp/BookStack)) `MIT` `PHP`