LtsWidgets: Qt6 API fixes complete

- QComboBox::activated signal: QString→int parameter (lts_text_editor)
- qAsConst→std::as_const (5 files)
- localPos()→position() (lts_height_plot_widget)
- setMargin→setContentsMargins (tests/window.cpp)
- CMAKE_AUTOUIC OFF + include in header for MOC
- enterEvent(QEnterEvent*) signature fixes
- QRegExp→QRegularExpression replacements

All LtsWidgets module files now Qt6-compatible.

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/lts_multi_range_spinbox.cpp

@@ -75,7 +75,7 @@ void LtsMultiRangeSpinBox::fixup(QString &str) const
 
 QValidator::State LtsMultiRangeSpinBox::validateAll(QString &input, int &pos)
 {
-  for(QPair<int,int> range : qAsConst(m_rangesList))
+  for(QPair<int,int> range : std::as_const(m_rangesList))
   {
     QIntValidator validator(range.first, range.second);
     QValidator::State valState = validator.validate(input, pos);
@@ -127,7 +127,7 @@ void LtsMultiRangeSpinBox::setRanges(const QVector<QPair<int, int>> &ranges)
 
   QStringList rangeStrings;
   rangeStrings.reserve(m_rangesList.size());
-  for (const QPair<int,int> &range : qAsConst(m_rangesList))
+  for (const QPair<int,int> &range : std::as_const(m_rangesList))
     rangeStrings << tr("%1-%2%3").arg(range.first).arg(range.second).arg(suffix());
   setToolTip(tr("Ranges:\n%1").arg(rangeStrings.join(QStringLiteral(",\n"))));
 }