[#4243] Tweaks to the new var-dumper component

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.6
| Fixed tickets | none

Hi guys!

This follows after #4243 - the best way to review it was to merge, read from scratch, and make these final tweaks. As always, I've certainly made some mistakes, so I appreciate the review.

Thanks!
Well strictly speaking, this string is not the same as the previous one (indetation and line breaks), thus the screenshot does not match the actual dump output of this new string.