Add new comment to Minor inconvenience when saving projects

I meant sending the extension if it didn't exist, not figuring out the user's selection.

I've tried this and it seems to work:

qtractorMainForm.cpp line 2213

		// Always avoid to store session on extracted directories...
		sFilename = sessionArchivePath(sFilename);
		// Try to rename as if a backup is about...
		sFilename = sessionBackupPath(sFilename);
		//  NEW>> We ensure that filename adds the default extension if it is missing.
		if (! (sFilename.endsWith(".qtr") ||
			sFilename.endsWith(".qts") ||
			sFilename.endsWith(".qtz") ||
			sFilename.endsWith(".qtt")) ) {
			sFilename = sFilename + "." + sExt;
		}
	#if 1//QT_VERSION < QT_VERSION_CHECK(4, 4, 0)
		sFilename = QFileDialog::getSaveFileName(pParentWidget,
			sTitle, sFilename, sFilter, nullptr, options);
	#else