Update README.md

Author: thomas-zahner

README.md

@@ -3,7 +3,7 @@ A collection of use-cases and scripts to make [lychee] compatible with additiona
 **Your use-case or file format is not yet documented?
 Feel free to file an issue or create a PR!**
 
-Out of the box lychee supports HTML, Markdown and plain text formats.
+Out of the box lychee supports HTML and Markdown file formats.
 More precisely, HTML files are parsed as HTML5 with the use of the [html5ever] parser.
 Markdown files are treated as [CommonMark] with the use of [pulldown-cmark].