feature #40554 [Contracts] Add TranslatorInterface::getLocale() (nicolas-grekas)

This PR was merged into the 5.3-dev branch.

Discussion
----------

[Contracts] Add `TranslatorInterface::getLocale()`

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | yes
| Tickets       | Fix #40380
| License       | MIT
| Doc PR        | -

As discussed in https://github.com/symfony/symfony/issues/40380

Commits
-------

45d9a36794 [Contracts/Translation] Add `TranslatorInterface::getLocale()`

src/Symfony/Bridge/Twig/Tests/Extension/Fixtures/StubTranslator.php

@@ -19,4 +19,9 @@ class StubTranslator implements TranslatorInterface
     {
         return '[trans]'.strtr($id, $parameters).'[/trans]';
     }
+
+    public function getLocale(): string
+    {
+        return 'en';
+    }
 }

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Compiler/DataCollectorTranslatorPassTest.php

@@ -111,4 +111,9 @@ class TranslatorWithTranslatorBag implements TranslatorInterface
     public function trans(string $id, array $parameters = [], string $domain = null, string $locale = null): string
     {
     }
+
+    public function getLocale(): string
+    {
+        return 'en';
+    }
 }

src/Symfony/Component/Translation/PseudoLocalizationTranslator.php

@@ -108,6 +108,11 @@ final class PseudoLocalizationTranslator implements TranslatorInterface
         return $trans;
     }
 
+    public function getLocale(): string
+    {
+        return $this->translator->getLocale();
+    }
+
     private function getParts(string $originalTrans): array
     {
         if (!$this->parseHTML) {

src/Symfony/Contracts/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Add `HttpClientInterface::withOptions()`
+ * Add `TranslatorInterface::getLocale()`
 
 2.3.0
 -----

src/Symfony/Contracts/Translation/TranslatorInterface.php

@@ -13,6 +13,8 @@ namespace Symfony\Contracts\Translation;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @method string getLocale() Returns the default locale
  */
 interface TranslatorInterface
 {

src/Symfony/Contracts/Translation/TranslatorTrait.php

@@ -32,6 +32,8 @@ trait TranslatorTrait
 
     /**
      * {@inheritdoc}
+     *
+     * @return string
      */
     public function getLocale()
     {