DEV: (cmds) add GCRASETVALUE command page

[dwdougherty]

Redis 8.8 feature

Also includes changes to add GCRA and GCRASETVALUE to a new group called rate_limit (rate limiting).

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Note

Low Risk
Documentation-only updates; main risk is inaccurate or inconsistent command syntax/behavior descriptions across pages.

Overview
Documents Redis 8.8 features and command surface changes. Adds new command docs for GCRA (rate limiting), GCRASETVALUE (internal), and XIDMPRECORD (internal), plus a new Rate limiting guide and a new rate_limit command group filter entry.

Updates existing command/reference docs to reflect Redis 8.8 behavior and observability: ACL LOAD comment-line support, new CLIENT LIST fields, and expanded INFO/commandstats metrics (including slowlog-derived stats). Also extends JSON.SET with the FPHA option (and diagrams/examples), updates TimeSeries range docs to support multiple comma-separated aggregators (and disallow GROUPBY/REDUCE when multiple aggregators are used), and refreshes a few ancillary docs (CLI navigation, supported OS/version tables, minor wording fixes).

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[github-actions]

DOC-6473

[github-actions]

Staging links:
https://redis.io/docs/staging/DOC-6473/commands/gcra/
https://redis.io/docs/staging/DOC-6473/commands/gcrasetvalue/

[jit-ci]

🛡️ Jit Security Scan Results

✅ No security findings were detected in this PR

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^{Security scan by Jit}

[dwdougherty]

Thank you, @cmilesb!