DokuWiki: add missing word to description (#3424)

DokuWiki:  "All data is stored in plain files" >  "All data is stored in plain text files"

"Plain files" is not clearly descriptive and plain text files (i.e. can be read in a text editor) is the main draw of DokuWiki.

README.md

@@ -2047,7 +2047,7 @@ _See also: [Wikimatrix](https://www.wikimatrix.org/), [Wiki Engines - WikiIndex]
 - [Cowyo](https://github.com/schollz/cowyo) - Cowyo is a feature-rich wiki for minimalists. ([Demo](https://cowyo.com)) `MIT` `Go`
 - [django-wiki](https://github.com/django-wiki/django-wiki) - Wiki system with complex functionality for simple integration and a superb interface. Store your knowledge with style: Use django models. ([Demo](https://demo.django-wiki.org/)) `GPL-3.0` `Python`
 - [Documize](https://documize.com) - Modern Docs + Wiki software with built-in workflow, single binary executable, just bring MySQL/Percona. ([Source Code](https://github.com/documize/community)) `AGPL-3.0` `Go`
-- [Dokuwiki](https://www.dokuwiki.org/DokuWiki) - Easy to use, lightweight, standards-compliant wiki engine with a simple syntax allowing reading the data outside the wiki. All data is stored in plain files, therefore no database is required. ([Source Code](https://github.com/splitbrain/dokuwiki)) `GPL-2.0` `PHP`
+- [Dokuwiki](https://www.dokuwiki.org/DokuWiki) - Easy to use, lightweight, standards-compliant wiki engine with a simple syntax allowing reading the data outside the wiki. All data is stored in plain text files, therefore no database is required. ([Source Code](https://github.com/splitbrain/dokuwiki)) `GPL-2.0` `PHP`
 - [Gitit](https://github.com/jgm/gitit) - Wiki program that stores pages and uploaded files in a git repository, which can then be modified using the VCS command line tools or the wiki's web interface. `GPL-2.0` `Haskell`
 - [Gollum](https://github.com/gollum/gollum) - Simple, Git-powered wiki with a sweet API and local frontend. `MIT` `Ruby`
 - [Instiki](https://golem.ph.utexas.edu/wiki/instiki/show/HomePage) - Instiki is a wiki clone so pretty and easy to set up, you'll wonder if it’s really a wiki. Runs on Rails and focuses on portability and stability. ([Source Code](https://github.com/parasew/instiki)) `Ruby` `Ruby`