docs: explain dialect requirement for lambda examples

[Prajwal-k-tech]

Which issue does this PR close?

• Closes Lambda examples in the SQL function docs fail with the default dialect #25960

Rationale for this change

The SQL reference examples for these higher-order array functions use lambda expressions, but the default SQL dialect does not parse the -> syntax. The examples work when a lambda-capable dialect is selected, and the current descriptions do not explain that requirement.

What changes are included in this PR?

• Add a note to the user documentation for any_match, array_filter, array_first, and array_transform explaining that lambdas require a supporting dialect and showing how to select DuckDB.
• Regenerate the scalar function reference from the source #[user_doc] descriptions.

This change was prepared with AI assistance. The patch and generated documentation were checked against the issue and repository guidance.

What is the testing strategy for this PR?

This is a documentation-only change, so no runtime tests were added. Verified the generated reference with ./dev/update_function_docs.sh, ran the repository documentation Prettier check, cargo +1.99.0 fmt --all -- --check, cargo clippy --all-targets --all-features -- -D warnings, and git diff --check.

Are there any user-facing changes?

Yes. The SQL function reference now tells users which dialect setting is needed to run the lambda examples.

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