Add plugin for native autocompletion from Symfony 6

[malteschlueter]

Standards checklist:

• The PR title is descriptive.
• The PR doesn't replicate another PR which is already open.
• I have read the contribution guide and followed all the instructions.
• The code follows the code style guide detailed in the wiki.
• The code is mine or it's from somewhere with an MIT-compatible license.
• The code is efficient, to the best of my ability, and does not waste computer resources.
• The code is stable and I have tested it myself, to the best of my abilities.
• If the code introduces new aliases, I provide a valid use case for all plugin users down below.

Changes:

• Add plugin for native autocompletion from Symfony 6

Other comments:

Native auto-completion was introduced in Symfony 5.4, but only for bash.
As of Symfony 6.2, zsh is also supported, so I wanted to add it as a new plugin.

The code is generated by the Symfony command `php bin/console completion zsh'.

https://symfony.com/doc/current/console.html#console-completion
https://symfony.com/blog/new-in-symfony-6-2-console-improvements#zsh-shell-autocompletion