Twig 3: Spaceless deprecation

[acrobat]

Since twig/twig 3.12: Twig Filter "spaceless" is deprecated in src/Bundle/Resources/views/forms.html.twig at line 5.
Since twig/twig 3.12: Twig Filter "spaceless" is deprecated in src/Bundle/Resources/views/forms.html.twig at line 41.

[loic425]

I don't think someone is using these templates. We should remove them for 2.0. but still, thank you for the issue.