Add a developer tooling topic to Drupal core

This is a great idea!

The edited paragraph might need some thought, though, as the topic of development tools is less likely to be related to the core gates.

https://www.drupal.org/core-gates → would define what does the developer tooling gate mean :)

The issue to discuss the details of the core gate is ✨ Define core gate for 'developer tooling' Active

The changes look correct to me and agrees with the related policy discussion. I have no suggested changes.

MR looks good to me too.