minor symfony#57519 [Workflow] Add phpdoc about exception (VincentLanglet)

This PR was merged into the 7.2 branch.

Discussion
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[Workflow] Add phpdoc about exception

| Q             | A
| ------------- | ---
| Branch?       | 7.2
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        | Fix #...
| License       | MIT

I recently changed a `can` call to a `buildTransitionBlockerList` and got many exceptions.

When looking at the interface we could believe the behavior of these method are similar with
- can returning true/false
- buildTransitionBlockerList returning a list empty or not

But it's not true.
When we try to call `buildTransitionBlockerList` with a not defined transition,
- can return false
- buildTransitionBlockerList throw an exception

I think this should at least be mentioned in the PHPdoc.
Dunno if this need to wait 7.2 or can be done on previous versions.

cc `@lyrixx`

Commits
-------

66f3340 Add phpdoc about exception

Author: fabpot

src/Symfony/Component/Workflow/WorkflowInterface.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\Workflow;
 
 use Symfony\Component\Workflow\Exception\LogicException;
+use Symfony\Component\Workflow\Exception\UndefinedTransitionException;
 use Symfony\Component\Workflow\MarkingStore\MarkingStoreInterface;
 use Symfony\Component\Workflow\Metadata\MetadataStoreInterface;
 
@@ -38,6 +39,8 @@ public function can(object $subject, string $transitionName): bool;
 
     /**
      * Builds a TransitionBlockerList to know why a transition is blocked.
+     *
+     * @throws UndefinedTransitionException If the transition is not defined
      */
     public function buildTransitionBlockerList(object $subject, string $transitionName): TransitionBlockerList;