[docs2] Webdoc: fix Graphical user interface page ()

Merging branch 'docs2'  into 'main'.

See merge request !1471

hugo/content/gui/_index.md

@@ -6,17 +6,16 @@ weight = 30
 ## Running BornAgain through the GUI
 
 BornAgain comes with a graphical user interface (GUI).
-Based on the library Qt5, it has a native look and feel
+Based on the library Qt6, it has a native look and feel
 under all three supported operating systems. It allows
 users to view experimental and simulated data, to set up
 and parameterize physical models, and to run fits.
 
-A graphical sample editor allows users to assemble
-multilayer models by drag-and-drop. Model components like
+A graphical sample editor allows users to set up
+multilayer models. Model components like
 embedded particles or inter-particle correlation functions are
-represented by boxes that are connected by flexible lines to
-their parent components. Simultaneously, the real-space
-structure of the sample, or any of its components, can be
+represented by groupboxes with editable fields. Simultaneously, 
+the real-space structure of the sample, or any of its components, can be
 shown in an interactive 3D visualization. This provides
 users with feedback as to whether the model, constructed
 in abstract terms in the sample editor, corresponds to their