Reword comments.

fdbclient/BackupContainerFileSystem.actor.cpp

@@ -892,8 +892,9 @@ class BackupContainerFileSystemImpl {
 	}
 
 	// Get a set of files that can restore the given "keyRangesFilter" to the "targetVersion".
-	// If "keyRangesFilter" is empty, the restore will recover the whole database. It's generally
-	// a good idea to specify "keyRangesFilter" to reduce the number of files for restore times.
+	// If "keyRangesFilter" is empty, the file set will cover all key ranges present in the backup.
+	// It's generally a good idea to specify "keyRangesFilter" to reduce the number of files for
+	// restore times.
 	//
 	// If "logsOnly" is true, then only log files are returned and "keyRangesFilter" is ignored,
 	// because the log can contain mutations of the whole key space, unlike range files that each