Changes: document Qt6 and CalamaresUtils

CHANGES-3.3

@@ -11,9 +11,7 @@ the history of the 3.2 series (2018-05 - 2022-08).
 
 The very first we-will-call-it-3.3 release! One of the big changes is that
 Calamares -- the core and nearly all of the modules in this repository --
-are compatible with Qt6. This means that a Qt6-based distribution can use
+are compatible with Qt6.
-Calamares without including another version of Qt. Note that some KDE
-Frameworks are required as well, and those need to be Qt6-based as well.
 
 This release contains contributions from (alphabetically by first name):
  - Adriaan de Groot
@@ -22,6 +20,14 @@ This release contains contributions from (alphabetically by first name):
  - Ivan Borzenkov
 
 ## Core ##
+ - Qt6 compatibility. You can choose Qt5 (with KDE Frameworks 5) as before,
+   or choose Qt6 (with KDE Frameworks 6). This means that a Qt6-based Linux
+   distribution can use Calamares without needing an extra version of Qt.
+   Note that some KDE Frameworks are required as well, and those need to be
+   Qt6-based also (and are not released as of September 2023).
+ - C++ namespaces have been shuffled around and `CalamaresUtils` has been
+   retired. This has an effect on all C++ plugins, since this is neither
+   a binary- nor source-compatible change.
 
 ## Modules ##
  - *keyboard* module can now be explicitly configured to use X11 keyboard