minor symfony#58064 [Validator] Add @template on CompoundConstraintTestCase (alexandre-daubois)

This PR was merged into the 7.2 branch.

Discussion
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[Validator] Add ``@template`` on `CompoundConstraintTestCase`

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

While writing [the docs](symfony/symfony-docs#20150), I realized ``@template`` could be added. Moreover, it is already present on `ConstraintValidatorTestCase`.

Commits
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618215a [Validator] Add ``@template`` on CompoundConstraintTestCase`

Author: nicolas-grekas

src/Symfony/Component/Validator/Test/CompoundConstraintTestCase.php

@@ -27,6 +27,8 @@
  * A test case to ease testing Compound Constraints.
  *
  * @author Alexandre Daubois <alex.daubois@gmail.com>
+ *
+ * @template T of Compound
  */
 abstract class CompoundConstraintTestCase extends TestCase
 {
@@ -119,5 +121,8 @@ protected function assertNoViolation(): void
         $this->assertSame(0, $violationsCount, \sprintf('No violation expected. Got %d.', $violationsCount));
     }
 
+    /**
+     * @return T
+     */
     abstract protected function createCompound(): Compound;
 }

src/Symfony/Component/Validator/Tests/Test/CompoundConstraintTestCaseTest.php

@@ -19,6 +19,9 @@
 use Symfony\Component\Validator\Test\CompoundConstraintTestCase;
 use Symfony\Component\Validator\Tests\Fixtures\DummyCompoundConstraint;
 
+/**
+ * @extends CompoundConstraintTestCase<DummyCompoundConstraint>
+ */
 class CompoundConstraintTestCaseTest extends CompoundConstraintTestCase
 {
     protected function createCompound(): Compound