[hotfix][docs] Fix grammar errors in documentation

[kiyeonjeon21]

What is the purpose of the change

Fix minor grammar errors found across multiple documentation pages:

• Duplicated words ("or or", "be be")
• Incorrect article before consonant sounds ("an breaking", "an procedure", "an time", "an record", "an job", "an java.lang.Iterable", "an user-defined-function")
• Incorrect article before vowel sounds ("a event", "a element", "a operator", "a application")
• Garbled article pair ("a the corresponding")

Brief change log

• Fixed duplicated "or" in batch_shuffle.md
• Fixed duplicated "be" in create.md
• Fixed "a the" to "the" in testing.md
• Fixed "an" to "a" where followed by consonant sounds in flink-2.2.md, call.md, window-tvf.md, hints.md, debugging_classloading.md, udfs.md, raw.md
• Fixed "a" to "an" where followed by vowel sounds in events.md, joins.md, application_parameters.md, upgrading.md

Verifying this change

This change is a trivial documentation text fix that does not affect any runtime behavior.

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: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no

[flinkbot]

CI report:

• 8dbacb4 Azure: FAILURE

Bot commands

The @flinkbot bot supports the following commands:

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

[spuru9]

LGTM +1

[davidradl]

the changes look good - please can you update the Chinese docs with the same changes as required.

[kiyeonjeon21]

Thanks for the review! I checked the Chinese docs and applied the same fixes where applicable.

[raminqaf]

Thanks for the review! I checked the Chinese docs and applied the same fixes where applicable.

Thanks for the contribution. If you have native or professional proficiency in Chinese, update the Chinese documentation. We are looking for nuanced, manual translations rather than AI-assisted translations for this specific task.

[kiyeonjeon21]

I don't have proficiency in Chinese, so I can't help with Chinese translations. The changes I pushed to the Chinese docs are not translations — they are the same English grammar fixes (e.g., "or or" → "or", "an" → "a") that also existed in the Chinese documentation files.