a_fujisaki

Add types for singleton methods of GzipReader. Also, fix the incorrect types.

Add type to CSV::Row#initialize in stdlib because the type does not exist. The content of the headers array is `untyped`, because any object can be specified as long as it...

activemodel: add ActiveModel::Error in 7.0

6

**Background** ActiveModel::Error was added in 6.1. However, 7.0 types have not kept up with this change because it use types created from 6.0 source code. - 6.0: https://github.com/rails/rails/blob/v6.1.7.8/activemodel/lib/active_model/errors.rb - 7.0:...