[Feature] fix docs in Streaming-Synchronous-Generation

[zhaochenyang20]

Checklist

• 1. If the issue you raised is not a feature but a question, please raise a discussion at https://github.com/sgl-project/sglang/discussions/new/choose Otherwise, it will be closed.
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Motivation

Fix this https://docs.sglang.ai/backend/offline_engine_api.html#Streaming-Synchronous-Generation

To long generated contents and it seems to be wrong.

Related resources

No response

[zhaochenyang20]

And this Streaming-Synchronous-Generation https://docs.sglang.ai/backend/offline_engine_api.html#Streaming-Asynchronous-Generation