Add homonphone replacer example for Python API.

[csukuangfj]

To run the example for the following hotwords

国安|雏鹰|飞龙|雄鹰|祥鹏

do the following.

1. Use
   https://colab.research.google.com/drive/1-Djy8uYqlM4Z6zBaQkzcJO9JkfUAZGkV?usp=sharing
   to get replacer2.fst.
   We have attached it below
   replace2.fst.zip

2. Download lexicon.txt and dict.tar.bz2 from
   https://github.com/k2-fsa/sherpa-onnx/releases/tag/hr-files

wget https://github.com/k2-fsa/sherpa-onnx/releases/download/hr-files/lexicon.txt
wget https://github.com/k2-fsa/sherpa-onnx/releases/download/hr-files/dict.tar.bz2
tar xvf dict.tar.bz2
rm dict.tar.bz2

3. Download an ASR model from
   https://k2-fsa.github.io/sherpa/onnx/pretrained_models/online-transducer/zipformer-transducer-models.html#csukuangfj-sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20-bilingual-chinese-english

4. Run it

# 国安|雏鹰|飞龙|雄鹰|祥鹏
python3 ./python-api-examples/speech-recognition-from-microphone-with-endpoint-detection.py \
  --tokens ./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/tokens.txt \
  --encoder ./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/encoder-epoch-99-avg-1.onnx \
  --decoder ./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/decoder-epoch-99-avg-1.onnx \
  --joiner ./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/joiner-epoch-99-avg-1.onnx \
  --hr-dict-dir ./dict \
  --hr-lexicon ./lexicon.txt \
  --hr-rule-fsts ./replace2.fst