[FLINK-30731][docs]Translate "Set Operations" page of "Querys" into C…

[NightRunner]

Page "Application Development"/"Table API&SQL"/"SQL"/"Queries"/Set Operations translate to chinese.

What is the purpose of the change

Translate /dev/table/sql/queries/set-ops.md

Brief change log

Translate /dev/table/sql/queries/set-ops.md

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

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? no

[flinkbot]

CI report:

• a9684b8 Azure: FAILURE

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[wuchong]

LGTM. Will merge it.