filetree: Rename Show Active to Show Active Document

It's not clear otherwise what is meant. What active thing are we showing
where? This at least clarifies that we show the active document
somehwere.

addons/filetree/katefiletreeplugin.cpp

@@ -256,7 +256,7 @@ void KateFileTreePluginView::setupActions()
     connect(aNext, &QAction::triggered, m_fileTree, &KateFileTree::slotDocumentNext);
 
     auto aShowActive = actionCollection()->addAction(QStringLiteral("filetree_show_active_document"));
-    aShowActive->setText(i18n("&Show Active"));
+    aShowActive->setText(i18n("&Show Active Document"));
     aShowActive->setIcon(QIcon::fromTheme(QStringLiteral("folder-sync")));
     connect(aShowActive, &QAction::triggered, this, &KateFileTreePluginView::showActiveDocument);