Issue on getting-started/server-requirements

## Affected page(s)

https://docs.modx.com/3.x/en/getting-started/server-requirements#php

## What needs to be improved?

The list with required PHP extensions is incomplete. The complete list can be found here: https://github.com/modxcms/revolution/blob/789a1c719405535b42b4612731e678b6cb9f6301/composer.json#L62-L72

## Relevant context

I guess all languages are affected by this.
