unify the prettier versions

[cj-zhukov]

Which issue does this PR close?

• Closes #Unify the Prettier versions #20024.

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[cj-zhukov]

High-level overview

This PR standardizes the Prettier version used across DataFusion’s documentation-related scripts.

During the review, I identified several scripts in both dev/ and ci/ directories that invoked Prettier with different pinned versions. To remove this inconsistency, the scripts were updated to define a local PRETTIER_VERSION variable and use the same Prettier version everywhere.

The chosen approach keeps the solution intentionally simple:

• no new shared scripts or infrastructure were introduced
• existing script behavior remains unchanged
• all Prettier invocations are now aligned to a single version

This provides consistent formatting behavior across local workflows and CI, while keeping the change minimal and easy to review.

As a future improvement, the Prettier version could be centralized (for example, via a shared script or config) if additional tooling versions need to be managed in a similar way. For now, keeping the version local to each script avoids adding new dependencies and keeps the scope focused.

[cj-zhukov]

@Jefffrey since you originally pointed this #19750 (comment), it would be great if you could take a look at this PR. Your feedback or any improvements would be much appreciated.

[Jefffrey]

Would be nice if we figured a way to unify these, but aligning them is a good first step; perhaps leave the original issue open for this?