minor #16252 Correct spelling & grammar in 4.4 migration.rst (gnito-org)

This PR was merged into the 4.4 branch.

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Correct spelling & grammar in 4.4 migration.rst

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90b0776 Correct spelling & grammar in 4.4 migration.rst

Author: javiereguiluz

migration.rst

@@ -223,7 +223,7 @@ unique approach for migration. This guide shows two examples of commonly used
 approaches, which you can use as a base for your own approach:
 
 * `Front Controller with Legacy Bridge`_, which leaves the legacy application
-  untouched and allows to migrate it in phases to the Symfony application.
+  untouched and allows migrating it in phases to the Symfony application.
 * `Legacy Route Loader`_, where the legacy application is integrated in phases
   into Symfony, with a fully integrated final result.