[DOC]Update watermark column type

[hehuiyuan]

What is the purpose of the change

https://nightlies.apache.org/flink/flink-docs-release-1.18/docs/dev/table/sql/create/#watermark

Add rowtime colunm type TIMESTAMP_LTZ(3)

Brief change log

Add rowtime colunm type TIMESTAMP_LTZ(3)

Verifying this change

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

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? ( no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

CI report:

• cfb92fb619cfdbaa4b610d4c95dae57922afec18 Azure: SUCCESS

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