docs: add documentation for COMMENT ON statement

[Copilot]

What's Changed in this PR

Documents the COMMENT feature from GreptimeTeam/greptimedb#7060 using the correct COMMENT ON SQL syntax.

Changes

• New documentation files:
  • Created docs/reference/sql/comment.md documenting the COMMENT ON statement in English
  • Created i18n/zh/docusaurus-plugin-content-docs/current/reference/sql/comment.md with Chinese translation
  • Created versioned_docs/version-1.0/reference/sql/comment.md for version 1.0 (latest stable release)
  • Created i18n/zh/docusaurus-plugin-content-docs/version-1.0/reference/sql/comment.md with Chinese translation for version 1.0
• COMMENT ON TABLE: Added syntax and examples for adding/removing table comments
• COMMENT ON COLUMN: Added syntax and examples for adding/removing column comments
• COMMENT ON FLOW: Added syntax and examples for adding/removing flow comments
• Sidebar updates:
  • Added reference/sql/comment to sidebars.ts in alphabetical order
  • Updated versioned_sidebars/version-1.0-sidebars.json to include comment.md
• Documentation notes: Included information on viewing comments via SHOW CREATE and INFORMATION_SCHEMA tables

Example Usage

-- Add table comment
COMMENT ON TABLE system_metrics IS 'System monitoring metrics collected every minute';

-- Add column comment
COMMENT ON COLUMN system_metrics.cpu_usage IS 'CPU usage percentage (0-100)';

-- Add flow comment
COMMENT ON FLOW temperature_monitoring IS 'Monitors temperature sensors and alerts on high values';

-- Remove comments (set to NULL)
COMMENT ON TABLE system_metrics IS NULL;
COMMENT ON COLUMN system_metrics.cpu_usage IS NULL;
COMMENT ON FLOW temperature_monitoring IS NULL;

Comments are viewable via SHOW CREATE TABLE/SHOW CREATE FLOW or by querying INFORMATION_SCHEMA.TABLES/INFORMATION_SCHEMA.COLUMNS/INFORMATION_SCHEMA.FLOWS.

Checklist

• Please confirm that all corresponding versions of the documents have been revised.
• Please ensure that the content in sidebars.ts matches the current document structure when you changed the document structure.
• This change requires follow-up update in localized docs.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Update docs for feat: table/column/flow COMMENT</issue_title>
<issue_description>A document change request is generated from GreptimeTeam/greptimedb#7060</issue_description>

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

• Fixes Update docs for feat: table/column/flow COMMENT #2166

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View logs

[waynexia]

@copilot refer to tests/cases/standalone/common/comment.sql for SQL grammar

[Copilot]

@copilot refer to tests/cases/standalone/common/comment.sql for SQL grammar

Fixed in commit 282f509. I reviewed the test file and corrected the documentation to use the actual COMMENT ON TABLE/COLUMN/FLOW IS 'comment' syntax instead of the incorrect ALTER TABLE syntax I initially documented. Created a new docs/reference/sql/comment.md file with proper examples matching the test cases.

[waynexia]

@copilot add the Chinese doc correspondingly

[Copilot]

@copilot add the Chinese doc correspondingly

Added in commit 3761ce2. Created the Chinese documentation at i18n/zh/docusaurus-plugin-content-docs/current/reference/sql/comment.md with translations for all sections including COMMENT ON TABLE, COMMENT ON COLUMN, and COMMENT ON FLOW.

[fengjiachun]

@copilot Also need to add the documentation for the latest stable release.

[Copilot]

@copilot Also need to add the documentation for the latest stable release.

Added in commit 0c35708. Created both English and Chinese documentation for version 1.0 (latest stable release) at:

• versioned_docs/version-1.0/reference/sql/comment.md
• i18n/zh/docusaurus-plugin-content-docs/version-1.0/reference/sql/comment.md
• Updated versioned_sidebars/version-1.0-sidebars.json to include the new documentation.

[fengjiachun]

LGTM