Tweaks after proofreading the 2.6 OptionsResolver stuff

Hi guys!

This is a proofread after merging #4159. There were enough changes there that the easiest way to handle things was to merge, re-read entirely, then open a PR with small tweaks. But largely, I am very happy with how the document turned out :).

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.6+
| Fixed tickets | --

Thanks!
```rst
[...] use the :phpfunction:`array_replace` function to fix that [...]
```