minor #13498 Adding bulma theme (eerison)

This PR was submitted for the 5.0 branch but it was merged into the master branch instead (closes #13498).

Discussion
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Adding bulma theme

TwigBridge - Adding Bulma theme

Pull request: symfony/symfony#36351
Issue: symfony/symfony#36248

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Commits
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175b708 Adding bulma theme

Author: javiereguiluz

form/form_themes.rst

@@ -39,10 +39,14 @@ in a single Twig template and they are enabled in the
 * `foundation_6_layout.html.twig`_, wraps each form field inside a ``<div>``
   element with the appropriate CSS classes to apply the default styles of the
   version 6 of `Foundation CSS framework`_.
+* `bulma_0_layout.html.twig`_, wraps each form field inside a ``<div>``
+  element with the appropriate CSS classes to apply the styles used by the
+  `Bulma CSS framework`_.
 
 .. versionadded:: 5.1
 
-    The ``foundation_6_layout.html.twig`` theme was introduced in Symfony 5.1.
+    The ``foundation_6_layout.html.twig`` and ``bulma_0_layout.html.twig``
+    themes were introduced in Symfony 5.1.
 
 .. tip::
 
@@ -633,6 +637,8 @@ is a collection of fields (e.g. a whole form), and not just an individual field:
 .. _`Bootstrap 4 CSS framework`: https://getbootstrap.com/docs/4.4/
 .. _`foundation_5_layout.html.twig`: https://github.com/symfony/symfony/blob/master/src/Symfony/Bridge/Twig/Resources/views/Form/foundation_5_layout.html.twig
 .. _`foundation_6_layout.html.twig`: https://github.com/symfony/symfony/blob/master/src/Symfony/Bridge/Twig/Resources/views/Form/foundation_6_layout.html.twig
+.. _`bulma_0_layout.html.twig`: https://github.com/symfony/symfony/blob/master/src/Symfony/Bridge/Twig/Resources/views/Form/bulma_0_layout.html.twig
 .. _`Foundation CSS framework`: https://get.foundation/
 .. _`Twig "use" tag`: https://twig.symfony.com/doc/2.x/tags/use.html
 .. _`Twig parent() function`: https://twig.symfony.com/doc/2.x/functions/parent.html
+.. _`Bulma CSS framework`: https://bulma.io