[TwigBundle] Enable #[AsTwigFilter], #[AsTwigFunction] and `#[AsTwi…

[fabpot]

Q	A
Feature PR	symfony/symfony#52748
PR author(s)	@GromNaN
Merged in	7.3

We created this issue to not forget to document this new feature. We would really appreciate if you can help us with this task. If you are not sure how to do it, please ask us and we will help you.

To fix this issue, please create a PR against the 7.3 branch in the symfony-docs repository.

Thank you! 😃

[GromNaN]

Related Twig documentation: https://twig.symfony.com/doc/3.x/advanced.html#using-php-attributes-to-define-extensions

I propose to revise the Create the Extension Class chapter and use attributes instead of getFilters.
The next chapter on Creating Lazy-Loaded Twig Extensions is not really relevant since extension will be lazy-loaded by default using attributes. Is it necessary to keep this documentation part?

[javiereguiluz]

Yes, I like this plan:

• Update all Twig examples to use the new attributes
• Add a versionadded directive (but only the first time) mentioning that the attributes were introduced in 7.3 and that in previous versions you had to use the getFilters() method, etc. Mentioning the old method names is important so folks used to the old methods can still find the page
• I'd keep the section of lazy-loaded extensions (remove it in 8.x docs?) but I'd add a mention to the fact that when using attributes this is not needed anymore

Anybody willing to submit a Pull Request to fix this? Thanks!