[Help wanted] Add doc about using Whisper with Ascend NPU

[csukuangfj]

We need to update
https://k2-fsa.github.io/sherpa/onnx/ascend/models.html
to include Whisper

See also #3009

[csukuangfj]

See also https://k2-fsa.github.io/sherpa/onnx/ascend/models.html#sherpa-onnx-ascend-910b-cann-8-0-whisper-medium-en