docs: fix Japanese language tag in example.py comment

Changed <|jp|> to <|ja|> to match the actual tokenizer implementation.

The LANGUAGES dict in cosyvoice/tokenizer/tokenizer.py defines 'ja' for Japanese,
not 'jp'. This fixes the misleading comment that could cause issues like #621.

Fixes #1683

example.py

@@ -18,7 +18,7 @@ def cosyvoice_example():
     # zero_shot usage
     for i, j in enumerate(cosyvoice.inference_zero_shot('收到好友从远方寄来的生日礼物，那份意外的惊喜与深深的祝福让我心中充满了甜蜜的快乐，笑容如花儿般绽放。', '希望你以后能够做的比我还好呦。', './asset/zero_shot_prompt.wav')):
         torchaudio.save('zero_shot_{}.wav'.format(i), j['tts_speech'], cosyvoice.sample_rate)
-    # cross_lingual usage, <|zh|><|en|><|jp|><|yue|><|ko|> for Chinese/English/Japanese/Cantonese/Korean
+    # cross_lingual usage, <|zh|><|en|><|ja|><|yue|><|ko|> for Chinese/English/Japanese/Cantonese/Korean
     for i, j in enumerate(cosyvoice.inference_cross_lingual('<|en|>And then later on, fully acquiring that company. So keeping management in line, interest in line with the asset that\'s coming into the family is a reason why sometimes we don\'t buy the whole thing.',
                                                             './asset/cross_lingual_prompt.wav')):
         torchaudio.save('cross_lingual_{}.wav'.format(i), j['tts_speech'], cosyvoice.sample_rate)