create rule

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/12/rules-views.html
Description:

Nowhere in the documentation is mentioned that rules can only be made on
tables without dropped columns and, much to my suprise, on empty tables
only. I wanted to use rules on existing tables to cater for
column-redaction, but this seems only possible by creating a new (empty)
table for all user to use and to hide the original table from everyone.
1. the documentation should state this (and not start with an example of use
of rules in views, which is a special case, I though).
2. the implementation should fix the only-on-empty tables issue (avoiding
having to change the documentation).