[hotfix][docs] Fix duplicate word typos in documentation

[jhanishant260]

What is the purpose of the change

Fix three duplicate-word typos in the user-facing documentation. Pure documentation hotfix — no functional changes.

Brief change log

• docs/content/docs/sql/reference/ddl/create.md — "can be be used" → "can be used"
• docs/content.zh/docs/sql/reference/ddl/create.md — same English typo in the not-yet-translated section
• docs/content/docs/ops/batch/batch_shuffle.md — "unstable or or under" → "unstable or under" (two occurrences)

Verifying this change

This change is a trivial typo fix in documentation and does not need 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
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• a3bcbd5 Azure: SUCCESS

Bot commands

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

[spuru9]

Thanks, Lgtm.

[Samrat002]

LGTM