[docs] Complete ZooKeeper client configuration documentation

[hanliu0830]

Purpose

Fixes #4336

The ZooKeeper configuration reference omits an existing client buffer setting and lists the wrong type for the maximum in-flight request count.

Brief change log

• Document zookeeper.client.max-buffer-size, including its integer type, default of 104857600 bytes (100 MiB), and mapping to the client's jute.maxbuffer. Clarify that it overrides the client configuration file value and that the server limit is configured separately.
• Correct zookeeper.client.max-inflight-requests from String to Integer.

Tests

• git diff --check passed.
• Verified that all 11 zookeeper.* keys in ConfigOptions are documented and that both changed rows match their types and defaults.
• npm run build -- --no-minify passed with Node.js 24 after preparing the versioned docs and blog. The build reported blog-tag and broken-anchor warnings on unmodified pages.
• Verified both changed rows in the generated Next configuration page.
• ./mvnw -N spotless:check validate passed with Java 11 (Spotless, zero Checkstyle violations, and zero unapproved licenses).
• No Java unit or integration tests were run for this documentation-only change.

API and Format

No API or storage format changes.

Documentation

Updates the existing ZooKeeper configuration table. No new feature is introduced.