[FLINK-29368][table-planner] Upgrade DESC statement docs for new desc syntax

[swuferhong]

What is the purpose of the change

This pr is aims to upgrade DESC statement docs for new desc syntax which will be realized in PR. This syntax was discussed in [FLIP-63]https://cwiki.apache.org/confluence/display/FLINK/FLIP-63%3A+Rework+table+partition+support).

• Upgrade desc statement docs
• Upgrade Chinese desc statement docs

Brief change log

• Upgrade desc statement docs
• Upgrade Chinese desc statement docs

Verifying this change

No testing.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? yes
• If yes, how is the feature documented? This is a document.

[flinkbot]

CI report:

• d1639a5 Azure: FAILURE

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