minor #1362 Fix the URL of a broken link (javiereguiluz)

This PR was merged into the 2.x branch.

Discussion
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Fix the URL of a broken link

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

Commits
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d9be436 Fix the URL of a broken link

src/Translator/doc/index.rst

@@ -155,4 +155,4 @@ https://symfony.com/doc/current/contributing/code/bc.html
 .. _`Symfony Translator`: https://symfony.com/doc/current/translation.html
 .. _`the Symfony UX initiative`: https://symfony.com/ux
 .. _StimulusBundle configured in your app: https://symfony.com/bundles/StimulusBundle/current/index.html
-.. _`ICU Message Format`: https://symfony.com/doc/current/translation/message_format.html
+.. _`ICU Message Format`: https://symfony.com/doc/current/reference/formats/message_format.html