Clarified description of some columns in system.view_refreshes

Why it matters

This update enhances the documentation of the system.view_refreshes system table by providing clearer descriptions for certain columns, helping users better interpret the information about materialized view refreshes and their statuses.

How to use it

Users can query the system.view_refreshes table as usual to monitor materialized view refresh activities, benefiting from the improved column descriptions for easier data interpretation.