[Core] Make PropertyItem column usage more clear

- Renamed dataProperty -> dataPropertyName because the function returns
  variants for the property name.
- Add an enum for the column to remove magic numbers

src/Gui/propertyeditor/PropertyItem.cpp

@@ -295,7 +295,7 @@ int PropertyItem::childCount() const
 
 int PropertyItem::columnCount() const
 {
-    return 2;
+    return PropertyItem::ColumnCount;
 }
 
 void PropertyItem::setReadOnly(bool ro)
@@ -649,7 +649,7 @@ void PropertyItem::setPropertyValue(const QString& value)
     setPropertyValue(value.toStdString());
 }
 
-QVariant PropertyItem::dataProperty(int role) const
+QVariant PropertyItem::dataPropertyName(int role) const
 {
     if (role == Qt::ForegroundRole && linked) {
         return QVariant::fromValue(QColor(0x20, 0xaa, 0x20));  // NOLINT
@@ -742,9 +742,8 @@ QVariant PropertyItem::dataValue(int role) const
 
 QVariant PropertyItem::data(int column, int role) const
 {
-    // property name
-    if (column == 0) {
-        return dataProperty(role);
+    if (column == PropertyItem::NameColumn) {
+        return dataPropertyName(role);
     }
 
     return dataValue(role);

src/Gui/propertyeditor/PropertyItem.h

@@ -130,6 +130,12 @@ class GuiExport PropertyItem: public QObject, public ExpressionBinding
     PROPERTYITEM_HEADER
 
 public:
+    enum Column {
+        NameColumn = 0,
+        ValueColumn = 1,
+        ColumnCount
+    };
+
     ~PropertyItem() override;
 
     /** Sets the current property objects. */
@@ -216,7 +222,7 @@ protected:
     void onChange() override;
 
 private:
-    QVariant dataProperty(int role) const;
+    QVariant dataPropertyName(int role) const;
     QVariant dataValue(int role) const;
     QString toString(const Py::Object&) const;
     QString asNone(const Py::Object&) const;