minor symfony#8199 Explained the edge-case where the use_referer option doesn't work (javiereguiluz)

This PR was squashed before being merged into the 2.7 branch (closes symfony#8199).

Discussion
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Explained the edge-case where the use_referer option doesn't work

This fixes symfony/symfony#17529 (comment).

Commits
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7a7a842 Explained the edge-case where the use_referer option doesn't work

Author: xabbuh

reference/configuration/security.rst

@@ -348,7 +348,14 @@ use_referer
 **type**: ``boolean`` **default**: ``false``
 
 If ``true``, the user is redirected to the value stored in the ``HTTP_REFERER``
-header when no previous URL was stored in the session.
+header when no previous URL was stored in the session. If the referrer URL is
+the same as the one generated with the ``login_path`` route, the user is
+redirected to the ``default_target_path`` to avoid a redirection loop.
+
+.. note::
+
+    For historical reasons, and to match the misspelling of the HTTP standard,
+    the option is called ``use_referer`` instead of ``use_referrer``.
 
 .. _reference-security-pbkdf2: