Add swift online punctuation

[yujinqiu]

Output result:

sh run-add-punctuations-online.sh
+ '[' '!' -d ../build-swift-macos ']'
+ '[' '!' -d ./sherpa-onnx-online-punct-en-2024-08-06 ']'
+ curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/punctuation-models/sherpa-onnx-online-punct-en-2024-08-06.tar.bz2
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:--  0:00:01 --:--:--     0
100 29.2M  100 29.2M    0     0  2578k      0  0:00:11  0:00:11 --:--:-- 3205k
+ tar xvf sherpa-onnx-online-punct-en-2024-08-06.tar.bz2
x ./sherpa-onnx-online-punct-en-2024-08-06/
x ./sherpa-onnx-online-punct-en-2024-08-06/model.int8.onnx
x ./sherpa-onnx-online-punct-en-2024-08-06/README.md
x ./sherpa-onnx-online-punct-en-2024-08-06/model.onnx
x ./sherpa-onnx-online-punct-en-2024-08-06/bpe.vocab
+ rm sherpa-onnx-online-punct-en-2024-08-06.tar.bz2
+ '[' '!' -e ./add-punctuation-online ']'
+ swiftc -lc++ -I ../build-swift-macos/install/include -import-objc-header ./SherpaOnnx-Bridging-Header.h ./add-punctuation-online.swift ./SherpaOnnx.swift -L ../build-swift-macos/install/lib/ -l sherpa-onnx -l onnxruntime -o ./add-punctuation-online
+ strip ./add-punctuation-online
+ export DYLD_LIBRARY_PATH=/Users/knight/pool/1w/punctuation/sherpa-onnx/swift-api-examples/../build-swift-macos/install/lib:
+ DYLD_LIBRARY_PATH=/Users/knight/pool/1w/punctuation/sherpa-onnx/swift-api-examples/../build-swift-macos/install/lib:
+ ./add-punctuation-online

result is:
How are you? I am fine. Thank you.

result is:
The African blogosphere is rapidly expanding, bringing more voices online in the form of commentaries, opinions, analyses, rants, and poetry.

[csukuangfj]

Thank you!

Left some minor comments. Otherwise, it looks good to me.

[csukuangfj]

Thank you for your contribution!