minor #14198 🚑 Fixed: "Could not find package annotations" in composer r… (albuquerque53)

This PR was submitted for the 5.1 branch but it was merged into the 4.4 branch instead.

Discussion
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🚑  Fixed: "Could not find package annotations" in composer r…

Apparently, the "annotations" package doesn't exists. I saw in packagist page that the routing component requires a 'doctrine/annotations: ~1.2'.
Packagist symfony/routing url: https://packagist.org/packages/symfony/routing

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Commits
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7ec805a 🚑 Fixed: "Could not find package annotations" in composer require

Author: javiereguiluz

routing.rst

@@ -27,7 +27,7 @@ Run this command once in your application to add support for annotations:
 
 .. code-block:: terminal
 
-    $ composer require annotations
+    $ composer require doctrine/annotations
 
 In addition to installing the needed dependencies, this command creates the
 following configuration file: