[PHP-WEBMASTER] [web-php] PR #1103: Additional redirects for mongodb set-to-book conversion

Pull Request: https://github.com/php/web-php/pull/1103
Author: jmikola

The first redirect was added in php/web-php#1100, but additional sections that no longer have their own page were missed. The original conversion was done in php/doc-en#3627 and php/doc-base#138.

https://jira.mongodb.org/browse/PHPC-1247