[improve] Add comment to emphasize using ; as separator in metadataServiceUri.

[visxu]

[improve] Add comment to emphasize using ; as separator in metadataServiceUri.

Fixes #xyz

Main Issue: #xyz

PIP: #xyz

Motivation

In bookkeeper.conf, parameter metadataServiceUri miss multiple zk servers example, sometimes take confusing.

Modifications

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository:

[github-actions]

@visxu Please select only one documentation label in your PR description.

[visxu]

Hi, @lhotari . Could you help to review it if you're available, thanks.