REMOVE old QT<= 5.14 code

Ubuntu 22.04  use qt 1.15.3.
In the code is still used qt code <5.10.
A cleanup was done by removing qT code version used in ubuntu 18.04.

src/Gui/PreferencePages/DlgSettingsEditor.cpp

@@ -76,11 +76,7 @@ DlgSettingsEditor::DlgSettingsEditor(QWidget* parent)
 
     setupConnections();
 
-#if QT_VERSION < QT_VERSION_CHECK(5, 10, 0)
-    ui->textEdit1->setTabStopWidth(40);
-#else
     ui->textEdit1->setTabStopDistance(40.0);
-#endif
 
     d = new DlgSettingsEditorP();
     QColor col;
@@ -173,17 +169,10 @@ void DlgSettingsEditor::setupConnections()
             this, &DlgSettingsEditor::onDisplayItemsCurrentItemChanged);
     connect(ui->colorButton, &ColorButton::changed,
             this, &DlgSettingsEditor::onColorButtonChanged);
-#if QT_VERSION < QT_VERSION_CHECK(5, 14, 0)
-    connect(ui->fontFamily, qOverload<const QString&>(&QComboBox::activated),
-            this, &DlgSettingsEditor::onFontFamilyActivated);
-    connect(ui->fontSize, qOverload<const QString&>(&PrefSpinBox::valueChanged),
-            this, &DlgSettingsEditor::onFontSizeValueChanged);
-#else
     connect(ui->fontFamily, &QComboBox::textActivated,
             this, &DlgSettingsEditor::onFontFamilyActivated);
     connect(ui->fontSize, &PrefSpinBox::textChanged,
             this, &DlgSettingsEditor::onFontSizeValueChanged);
-#endif
     // clang-format on
 }
 
@@ -213,11 +202,7 @@ void DlgSettingsEditor::setEditorTabWidth(int tabWidth)
 {
     QFontMetrics metric(font());
     int fontSize = QtTools::horizontalAdvance(metric, QLatin1Char('0'));
-#if QT_VERSION < QT_VERSION_CHECK(5, 10, 0)
-    ui->textEdit1->setTabStopWidth(tabWidth * fontSize);
-#else
     ui->textEdit1->setTabStopDistance(tabWidth * fontSize);
-#endif
 }
 
 void DlgSettingsEditor::saveSettings()