Functions: start generating String functions from source

[Blargian]

Summary

Start generating the String functions from source

Checklist

• Delete items not relevant to your PR
• URL changes should add a redirect to the old URL via https://github.com/ClickHouse/clickhouse-docs/blob/main/docusaurus.config.js
• If adding a new integration page, also add an entry to the integrations list here: https://github.com/ClickHouse/clickhouse-docs/blob/main/docs/integrations/index.mdx

[vercel]

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Project	Deployment	Preview	Comments	Updated (UTC)
clickhouse-docs	Error		Comment	Oct 17, 2025 1:55pm
clickhouse-docs-jp	Building	Preview	Comment	Oct 17, 2025 1:55pm

2 Skipped Deployments

Project	Deployment	Preview	Comments	Updated (UTC)
clickhouse-docs-ru	Ignored	Preview		Oct 17, 2025 1:55pm
clickhouse-docs-zh	Ignored	Preview		Oct 17, 2025 1:55pm

[Blargian]

Requires ClickHouse/ClickHouse#88673 first