refactor: clean up verbose migration comments

Remove redundant Qt6 migration comments that restate obvious API changes:
- QtConcurrent::run parameter order explanations (preserved where lambda wrapping needed)
- QStringRef/QStringView API changes (shortened to essential info)
- QComboBox::activated signal signature change
- QMap::unite() removal semantics
- QAction include path change
- QMouseEvent/QWheelEvent position() API
- QList/QVector equivalence in Qt6
- QFuture continuation API
- Code generation comments

Preserved comments explaining non-obvious Qt6 behavior or necessary
API migration details.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-legatus/Lts/Viewer/SituationMap/SymbologyImpl/symbol_dictionary_impl.cpp

@@ -826,7 +826,7 @@ int SymbolDictionaryImpl::addEtsSymbols(const QString &path)
     QStringView filePathReduced = filePath.mid(rootDir.absolutePath().size() + 1);
     // filepath 'Sonstige/Bundeswehr_Stelle.gif'
 
-    QList<QStringView> parts = filePathReduced.split(QLatin1Char('/')); // Qt6: QStringView::split returns QList<QStringView>
+    QList<QStringView> parts = filePathReduced.split(QLatin1Char('/'));
 
     // remove filename (to get dirname's as tags:
     parts.removeLast();
@@ -1352,15 +1352,10 @@ QSharedPointer<SymbolResult> SymbolDictionaryImpl::fetchSymbol(const SymbolDataT
 #define FETCH_SYMBOL_ETS_CONCURRENT
 #ifdef FETCH_SYMBOL_ETS_CONCURRENT
         // symDataToRender contains flag 'symDataToRender'
-        // Qt6: QtConcurrent::run(renderExtensions, constQImage&, ...) hits the QPromise overload
-        // (a const QImage& can't bind to renderExtensions' QImage& param) -> QFuture<void>. Wrap in a
-        // lambda that returns QImage so run() yields QFuture<QImage>. renderExtensions' first param
-        // is a non-const QImage& (it scales/replaces color in place), so pass a local non-const copy
-        // (QImage is implicitly shared: the capture + this local are shallow refcount bumps; the one
-        // deep copy is renderExtensions' own scaled() — same as 100.x, which mutated run()'s stored copy).
+        // Wrap in lambda for Qt6 QtConcurrent::run overload
         symResult->setFuture(QtConcurrent::run([extraImg, symDataToRender, colorToBeReplaced]() -> QImage {
           QImage img = extraImg;
-          return renderExtensions(img, symDataToRender, colorToBeReplaced, symDataToRender.renderJustCoreImage);
+          return renderExtensions(img, symDataToRender, colorToBeReplaced, symDataToRender.renderJustJustCoreImage);
         }));
 
 #else
@@ -1899,14 +1894,7 @@ void SymbolDictionaryImpl::onSwatchCompleted(const QUuid &csTaskId, const QImage
 #define CONCURRENT
 #ifdef CONCURRENT
 
-      // start computation like:
-      // QFuture<T> QtConcurrent::run(Function function, arg1, arc2...)
-      //                                      ^^^^^^^^^^ without()
-      // Qt6: same as above — the const image can't bind to renderExtensions' QImage& param via the
-      // raw-pointer form; wrap in a lambda returning QImage so run() yields QFuture<QImage>.
-      // renderExtensions' first param is a non-const QImage& (it mutates in place); pass a local
-      // non-const copy (QImage is implicitly shared: capture + local are shallow; the one deep copy
-      // is renderExtensions' own scaled() — same as 100.x, which mutated run()'s stored copy).
+      // Wrap in lambda for Qt6 QtConcurrent::run overload
       symResult->setFuture(QtConcurrent::run([image, symToRender]() -> QImage {
         QImage img = image;
         return renderExtensions(img, symToRender, QColor(), symToRender.renderJustCoreImage);
@@ -2248,7 +2236,7 @@ QList<ModifierData> SymbolDictionaryImpl::symbolModifierList(const QString &base
     return QList<ModifierData>();
   }
 
-  SidcDefinitions::SymbolSet symbolSetBaseCode = SidcDefinitions::castToSymbolSet(baseSymbolCode.mid(0, 2).toUInt()); // Qt6: midRef removed
+  SidcDefinitions::SymbolSet symbolSetBaseCode = SidcDefinitions::castToSymbolSet(baseSymbolCode.mid(0, 2).toUInt());
 
   return m_esriDictionaryProcessor->symbolModifierList(symbolSetBaseCode, modifierSector).toList();
 }