bug symfony#8607 fix security parameter name (hellomedia)

This PR was submitted for the master branch but it was merged into the 2.7 branch instead (closes symfony#8607).

Discussion
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fix security parameter name

change default_security_target to default_target_path

Commits
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f6e0c7d parameter name typo

Author: weaverryan

security/form_login.rst

@@ -34,7 +34,7 @@ several ways.
 Changing the default Page
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Define the ``default_security_target`` option to change the page where the user
+Define the ``default_target_path`` option to change the page where the user
 is redirected to if no previous page was stored in the session. The value can be
 a relative/absolute URL or a Symfony route name: