Refactor keyword handling and update to official database sources

[pseudomuto]

• Replace IsReservedKeyword driver method with Keywords() method
• Add shared IsReservedKeyword function in driver.go for consistency
• Update PostgreSQL keywords to official PostgreSQL 16 reserved words
• Update MySQL keywords to official MySQL 8.0 reserved words
• Optimize ClickHouse keywords based on non-reserved keyword philosophy
• Add comprehensive documentation with official sources and update dates
• Maintain test compatibility while improving keyword accuracy

[Copilot]

Pull Request Overview

This pull request refactors keyword handling across database drivers by replacing individual IsReservedKeyword methods with a standardized Keywords() method and centralizing keyword checking logic. It also updates all database-specific keyword lists to reflect official documentation for PostgreSQL 16, MySQL 8.0, and optimizes ClickHouse keywords based on their non-reserved philosophy.

• Replace driver-specific IsReservedKeyword methods with unified Keywords() methods
• Add shared IsReservedKeyword function in driver.go for consistent keyword checking
• Update keyword lists to official sources with comprehensive documentation

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
drivers/postgres/postgres.go	Remove keywords field and IsReservedKeyword method, add Keywords() method
drivers/postgres/keywords.go	Convert map to slice with PostgreSQL 16 official keywords and documentation
drivers/mysql/mysql.go	Remove keywords field and IsReservedKeyword method, add Keywords() method
drivers/mysql/keywords.go	Convert map to slice with MySQL 8.0 official keywords and documentation
drivers/clickhouse/clickhouse.go	Remove keywords field and IsReservedKeyword method, add Keywords() method
drivers/clickhouse/keywords.go	Convert map to slice with optimized ClickHouse keywords and documentation
driver_test.go	Update MockDriver to use Keywords() method instead of IsReservedKeyword
driver.go	Add shared IsReservedKeyword function and update NeedsQuoting to use it

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