Fix vosk-transcriber cli json format

[theone74]

Fix error UnboundLocalError: local variable 'monologue' referenced before assignment in transcriber.py line 102

vosk-transcriber -i test.wav -o test.json -t json -l en-gb

Traceback (most recent call last): File "/usr/local/bin/vosk-transcriber", line 8, in sys.exit(main()) File "/usr/local/lib/python3.10/dist-packages/vosk/transcriber/cli.py", line 86, in main transcriber.process_task_list(task_list) File "/usr/local/lib/python3.10/dist-packages/vosk/transcriber/transcriber.py", line 193, in process_task_list self.process_task_list_pool(task_list) File "/usr/local/lib/python3.10/dist-packages/vosk/transcriber/transcriber.py", line 189, in process_task_list_pool pool.map(self.pool_worker, task_list) File "/usr/lib/python3.10/multiprocessing/pool.py", line 367, in map return self._map_async(func, iterable, mapstar, chunksize).get() File "/usr/lib/python3.10/multiprocessing/pool.py", line 774, in get raise self._value File "/usr/lib/python3.10/multiprocessing/pool.py", line 125, in worker result = (True, func(*args, *kwds)) File "/usr/lib/python3.10/multiprocessing/pool.py", line 48, in mapstar return list(map(args)) File "/usr/local/lib/python3.10/dist-packages/vosk/transcriber/transcriber.py", line 168, in pool_worker processed_result = self.format_result(result) File "/usr/local/lib/python3.10/dist-packages/vosk/transcriber/transcriber.py", line 102, in format_result monologue["text"] += part["text"] UnboundLocalError: local variable 'monologue' referenced before assignment

[nshmyrev]

Thank you!