bug #14402 [FrameworkBundle][Translation] Check for 'xlf' instead of 'xliff' (xelaris)

This PR was merged into the 2.3 branch.

Discussion
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[FrameworkBundle][Translation] Check for 'xlf' instead of 'xliff'

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

There is no translation writer format named 'xliff', but 'xlf' only. So the TranslationUpdateCommand can't be called with 'output-format' == 'xliff' and the version info will never be shown.

The change from 'xliff' to 'xlf' was introduced in https://github.com/symfony/symfony/commit/2cb6260. The translation dumper alias was just renamed while the translation loader supports both 'xliff' and 'xlf'.

Commits
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aca1f28 [FrameworkBundle] Check for 'xlf' instead of 'xliff'

src/Symfony/Bundle/FrameworkBundle/Command/TranslationUpdateCommand.php

@@ -125,7 +125,7 @@ EOF
                 }
             }
 
-            if ($input->getOption('output-format') == 'xliff') {
+            if ($input->getOption('output-format') == 'xlf') {
                 $output->writeln('Xliff output version is <info>1.2</info>');
             }
         }