"68.4. Visibility Map" change suggestion.

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/12/storage-vm.html
Description:

Currently the documentation lists the line below; 

`Each heap relation has a Visibility Map (VM) to keep track of which pages
contain only tuples that are known to be visible to all active
transactions;`

Should it instead read like;

`Each heap relation has a Visibility Map (VM) to keep track of only those
pages that contain tuples known to be visible to all active transactions;`

After reading through the documentation and reading the first line, I first
thought that VM only kept track of pages that only had visible tuples.
Instead my understanding is that it shows which pages have any visible
tuples in them.