Add or link detailed PHP Extension Recommendations from Requirements page

[kirasong]

As a part of writing hosting best practices docs, the hosting community team audited WordPress for PHP extension use and documented the extensions that are recommended in the ​hosting handbook.

Since this isn't very discoverable, I'm opening this ticket to discuss how we might make it more so.

Initially, I think it might belong in, or in a subsection of: ​https://wordpress.org/about/requirements/

If not, it could be a link from there, or something else entirely. Thoughts?

[obenland]

I think linking to it would probably be the best first step. Do you have a copy suggestion for me that would include that link?

[kirasong]

Hey there! Sorry, Konstantin -- missed this on when you first commented. Apparently I've got to fix notifications.

I think something similar to this would work fine to get things started:
Following "That said, we can’t test every possible environment and each of the hosts on our hosting page supports the above and more with no problems.":

"For detailed PHP extension recommendations, see the Hosting Handbook."

[kirasong]

@obenland Just thought I'd double-check if you need anything else here.

[obenland]

@tellyworth, can you take a look at this when you get a chance?

[skithund]

The hosting handbook recommends installing mcrypt extension "for the sake of completeness".

​It has been deprecated in PHP 7.1.0 and was removed in 7.2.0. Sure, there's a PECL version available, but I wouldn't call hosting best practices recommending installing it.

[kirasong]

Replying to skithund:

The hosting handbook recommends installing mcrypt extension "for the sake of completeness".

<snip>

Thanks for the note! This is definitely not the intent of the wording. That section is meant to document other modules WordPress could use, but won't under optimal/best practice setup.

Specifically, the handbook says:

For the sake of completeness, below is a list of the remaining PHP modules WordPress may use in certain situations or if other modules are unavailable. These are fallbacks and not needed in an optimal environment, but installing them won't hurt.

How do you think we should reference them?
Happy to take suggestions for a change here, or you can submit a pull request ​on GitHub.

[coffee2code]

In 9855:

Main theme: Add link to detailed PHP extension recommendations from Requirements page.

Props mikeschroder.
Fixes #3632.