Add shebang lines to scripts in emformer_rnnt recipes (#2237)

Summary: Pull Request resolved: https://github.com/pytorch/audio/pull/2237

Reviewed By: mthrok

Differential Revision: D34267000

Pulled By: nateanl

fbshipit-source-id: 4c264aea6cf3fba5d8728d5fe60f9f471815852d

examples/asr/emformer_rnnt/eval.py

+#!/usr/bin/env python3
 import logging
 import pathlib
 from argparse import ArgumentParser

examples/asr/emformer_rnnt/global_stats.py

+#!/usr/bin/env python3
 """Generate feature statistics for training set.
 
 Example:

examples/asr/emformer_rnnt/librispeech/train_spm.py

+#!/usr/bin/env python3
 """Trains a SentencePiece model on transcripts across LibriSpeech train-clean-100, train-clean-360, and train-other-500.
 
 Example:

examples/asr/emformer_rnnt/mustc/train_spm.py

+#!/usr/bin/env python3
 """Train the SentencePiece model by using the transcripts of MuST-C release v2.0 training set.
 Example:
 python train_spm.py --mustc-path /home/datasets/

examples/asr/emformer_rnnt/pipeline_demo.py

+#!/usr/bin/env python3
 import logging
 import pathlib
 from argparse import ArgumentParser

examples/asr/emformer_rnnt/tedlium3/eval_pipeline.py

+#!/usr/bin/env python3
 import logging
 import pathlib
 from argparse import ArgumentParser, RawTextHelpFormatter

examples/asr/emformer_rnnt/tedlium3/train_spm.py

+#!/usr/bin/env python3
 """Train the SentencePiece model by using the transcripts of TED-LIUM release 3 training set.
 Example:
 python train_spm.py --tedlium-path /home/datasets/

examples/asr/emformer_rnnt/train.py

+#!/usr/bin/env python3
 import logging
 import pathlib
 from argparse import ArgumentParser