Add name to threads

This help identifying threads when debugging.
The naming scheme is using 'class/function name + variable name'.
Note that the length limitaion is 16 chars on linux. On Windows, the limit is 32767 chars.

PR #21403.

src/base/torrentfileswatcher.cpp

@@ -146,6 +146,7 @@ TorrentFilesWatcher::TorrentFilesWatcher(QObject *parent)
 
     m_asyncWorker->moveToThread(m_ioThread.get());
     connect(m_ioThread.get(), &QThread::finished, m_asyncWorker, &QObject::deleteLater);
+    m_ioThread->setObjectName("TorrentFilesWatcher m_ioThread");
     m_ioThread->start();
 
     load();