v.24.3Improvement

Added Comments for System Table Columns

Added comments for columns for more system tables. Continuation of https://github.com/ClickHouse/ClickHouse/pull/58356. #59016 (Nikita Mikhaylov).
Added descriptive comments to columns in more system tables to improve schema clarity and usability.

Why it matters

This feature enhances the self-documentation of ClickHouse system tables by providing detailed comments on columns. It helps users better understand the meaning and purpose of each column, making it easier to write queries and maintain the system.

How to use it

The comments are automatically added as part of system tables' schema metadata. Users can view these column comments by querying system tables' metadata or using compatible database tools that display column comments.