Improve docs

doc/helgobox/modules/ROOT/pages/app.adoc

@@ -1,4 +1,5 @@
 = Helgobox App
 
-[quote]
-include::partial$app-desc.adoc[]
+____
+include::partial$app-desc.adoc[]
+____

doc/helgobox/modules/ROOT/pages/plug-in.adoc

@@ -1,17 +1,15 @@
 = Helgobox Plug-In
 
-[quote]
+____
 include::partial$plug-in-desc.adoc[]
+It is complemented by the xref:app.adoc[].
+____
 
 The plug-in is fired up just like any other VST instrument in REAPER: By adding an instance of it to an FX chain:
 
 . Right-click the empty space in REAPER's track control panel
 . Select menu:Insert virtual instrument on new track...[]
 . Double-click entry "VSTi: Helgobox - ReaLearn & Playtime (Helgoboss)"
 
-Initially, you see the xref:plug-in/user-interface.adoc[plug-in window].
+Initially, you see the plug-in window.
 From there you can open the xref:app/user-interface.adoc[Helgobox App].
-
-include::partial$product-specific-info.adoc[]
-
-It is complemented by the xref:app.adoc[].