Disable the add/remove tile actions on startup

On startup there is no tileset open, so these actions should be
disabled. Normally they would not be visible anyway, but they appear in
the "Action Search" popup when enabled.

src/tiled/tileseteditor.cpp

@@ -248,6 +248,8 @@ TilesetEditor::TilesetEditor(QObject *parent)
 
     retranslateUi();
     connect(Preferences::instance(), &Preferences::languageChanged, this, &TilesetEditor::retranslateUi);
+
+    updateAddRemoveActions();
 }
 
 void TilesetEditor::saveState()
@@ -271,15 +273,15 @@ void TilesetEditor::restoreState()
 
 void TilesetEditor::addDocument(Document *document)
 {
-    TilesetDocument *tilesetDocument = qobject_cast<TilesetDocument*>(document);
+    auto *tilesetDocument = qobject_cast<TilesetDocument*>(document);
     Q_ASSERT(tilesetDocument);
 
-    TilesetView *view = new TilesetView(mWidgetStack);
+    auto *view = new TilesetView(mWidgetStack);
     view->setTilesetDocument(tilesetDocument);
     view->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
     view->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
 
-    TilesetModel *tilesetModel = new TilesetModel(tilesetDocument, view);
+    auto *tilesetModel = new TilesetModel(tilesetDocument, view);
     view->setModel(tilesetModel);
 
     connect(tilesetDocument, &TilesetDocument::tileWangSetChanged,
@@ -328,7 +330,7 @@ void TilesetEditor::removeDocument(Document *document)
 
 void TilesetEditor::setCurrentDocument(Document *document)
 {
-    TilesetDocument *tilesetDocument = qobject_cast<TilesetDocument*>(document);
+    auto *tilesetDocument = qobject_cast<TilesetDocument*>(document);
     Q_ASSERT(tilesetDocument || !document);
 
     if (document && DocumentManager::instance()->currentEditor() == this)
@@ -722,7 +724,7 @@ void TilesetEditor::addTiles(const QList<QUrl> &urls)
         if (!(dontAskAgain && rememberOption) && hasTileInTileset(url, *tileset)) {
             if (dontAskAgain)
                 continue;
-            QCheckBox *checkBox = new QCheckBox(tr("Apply this action to all tiles"));
+            auto *checkBox = new QCheckBox(tr("Apply this action to all tiles"));
             QMessageBox warning(QMessageBox::Warning,
                         tr("Add Tiles"),
                         tr("Tile \"%1\" already exists in the tileset!").arg(url.toString()),
@@ -961,7 +963,7 @@ void TilesetEditor::addWangSet(WangSet::Type type)
     if (!tileset)
         return;
 
-    WangSet *wangSet = new WangSet(tileset, QString(), type);
+    auto *wangSet = new WangSet(tileset, QString(), type);
     wangSet->setName(tr("Unnamed Set"));
     wangSet->setColorCount(1);