Add gscan2pdf (#258)

Co-authored-by: Loïc Reynier <[email protected]>

README.md

@@ -513,7 +513,8 @@ Clients for commercial social platforms that had their API access cut off in a w
 ### Document Scanners
 
 - [Decoder](https://apps.gnome.org/Decoder) - QR Codes scanner and generator `#rust` `#gtk4` `#libadwaita` `#gnome`.
-- [Document Scanner](https://apps.gnome.org/SimpleScan) - Document scanner using the SANE framework with crop and rotate editing features `#vala` `#libadwaita` `#gnome`.
+- [Document Scanner (SimpleScan)](https://apps.gnome.org/SimpleScan) - Document scanner using the SANE framework with crop and rotate editing features `#vala` `#gtk4``#libadwaita` `#gnome`.
+- [gscan2pdf](https://gscan2pdf.sourceforge.net) - Document scanner with cleaning and OCR features (on the scan or imported images incl. PDFs, DjVus or other file types) `#perl` `#gtk3`.
 
 ### Note-taking