Add docs for: [Workflow] Add colors to workflow dumps

[alexislefebvre]

Feature PR: symfony/symfony#29538

Now that #9476 has been fixed by superseded by #11209, and this last one is merged, we can document how to add colors.

For reference, see this nice example from @Korbeil 😃 : https://twitter.com/Korbeil_/status/1135914174603714565

[GitLuca]

Hi, any news on this documentation?
Symfony 4.3 is out but i cannot find any good documentation on how to change color to workflows. To be honest everything concerning workflows in Symfony is really fragmented and hard to find and understand. I tried to follow this example but without any luck https://symfony.com/blog/new-in-symfony-4-3-workflow-improvements

[javiereguiluz]

@GitLuca you are right. Sadly, there are so many components that the main Symfony Doc maintainers can't master all of them. We're mainly having problems with Workflow, Messenger and Serializer. We can't get enough contributors and reviewers.

[alexislefebvre]

@GitLuca you can find examples in the PR: https://github.com/symfony/symfony/pull/29538/files

Edit: oops I'm sorry I thought that it had YAML examples but it's not the case.

[alexislefebvre]

See #11907