Fix keyword spotting.

[csukuangfj]

See also #1417

Fixes #1417

CC @codepubs @brekov

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I think there is a bug in keyword spotting.

After the keyword is detected, the result.num_trailing_blanks of subsequent calls with Decode() is always 0.

This PR resets the stream after detecting a keyword to avoid that (Users should call it manually).

Also, it resets the stream automatically after detecting 1.5 seconds of silence.

[csukuangfj]

also， fixes #1235 @carcloudfly @yuyun2000

[yuyun2000]

This is cool, we recently discovered the blank parameter issue, but haven’t confirmed it yet.

[brekov]

cool! please supplement the API for JNI / Java / Kotlin. thanks.

[codepubs]

Windowsd demo已经解决，wasm场景还未解决问题，使用的是 https://github.com/csukuangfj/sherpa-onnx/tree/fix-kws 分支编译的，结果如下

0: {"start_time":0,"keyword":"小爱同学","timestamps":[40.96,41.32,41.6,49.32,49.36,49.52,49.56],"tokens":["x","iǎo","ài","t","óng","x","ué"]}
1: {"start_time":0,"keyword":"军哥牛逼","timestamps":[57.6,57.72,57.92,58,65,65.08,65.28,65.36],"tokens":["j","ūn","g","ē","n","iú","b","ī"]}

[csukuangfj]

Windowsd demo已经解决，wasm场景还未解决问题，使用的是 https://github.com/csukuangfj/sherpa-onnx/tree/fix-kws 分支编译的，结果如下

0: {"start_time":0,"keyword":"小爱同学","timestamps":[40.96,41.32,41.6,49.32,49.36,49.52,49.56],"tokens":["x","iǎo","ài","t","óng","x","ué"]}
1: {"start_time":0,"keyword":"军哥牛逼","timestamps":[57.6,57.72,57.92,58,65,65.08,65.28,65.36],"tokens":["j","ūn","g","ē","n","iú","b","ī"]}

可否帮忙再测试下？ wasm 例子，应该也修复了。

@codepubs

[csukuangfj]

cool! please supplement the API for JNI / Java / Kotlin. thanks.

@brekov Done. Please re-try.