docs: ALTER CONNECTION CONNECTOR WITH for online property updates

[Copilot]

Description

Documents the new ALTER CONNECTION ... CONNECTOR WITH syntax that enables online updates to connection properties (e.g., Kafka SASL credentials) without dropping dependent sources/sinks. Changes propagate atomically via barrier mutations, typically taking effect within seconds.

Added to /sql/commands/sql-alter-connection.mdx:

• Syntax and parameter specifications
• Behavior details: atomic catalog updates, validation, runtime propagation
• Limitations: restricted field subset per connector type, no nested connection references
• Complete example: Kafka SASL credential rotation using secrets

Example usage:

-- Rotate credentials without downtime
ALTER SECRET s_broker WITH (backend = 'meta') AS 'broker2.example.com:9092';
ALTER CONNECTION kafka_conn CONNECTOR WITH (
  properties.sasl.username = 'user2'
);
-- Dependent tables/sources/sinks continue running with new config

Related code PR

risingwavelabs/risingwave#22563

Related doc issue

Issue tracking this documentation update.

Checklist

• I have run the documentation build locally to verify the updates are applied correctly.
• For new pages, I have updated mint.json to include the page in the table of contents.
• All links and references have been checked and are not broken.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Document: feat: support ALTER CONNECTION CONNECTOR WITH</issue_title>
<issue_description>This issue tracks the documentation update needed for the merged PR risingwavelabs/risingwave-docs#22563.

Source PR URL: risingwavelabs/risingwave#22563
Source PR Merged At: 2025-12-17T12:16:24Z

If it is a major improvement that deserves a new page or a new section in the documentation, please check if we should label it as an experiment feature.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Document: feat: support ALTER CONNECTION CONNECTOR WITH #965

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