minor #11469 Update session.rst (FaizanFS)

This PR was merged into the 4.2 branch.

Discussion
----------

Update session.rst

<!--

If your pull request fixes a BUG, use the oldest maintained branch that contains
the bug (see https://symfony.com/roadmap for the list of maintained branches).

If your pull request documents a NEW FEATURE, use the same Symfony branch where
the feature was introduced (and `master` for features of unreleased versions).

-->

Commits
-------

15c680b Update session.rst

Author: javiereguiluz

session.rst

@@ -71,7 +71,7 @@ sessions, check their default configuration:
 Setting the ``handler_id`` config option to ``null`` means that Symfony will
 use the native PHP session mechanism. The session metadata files will be stored
 outside of the Symfony application, in a directory controlled by PHP. Although
-this usually simplify things, some session expiration related options may no
+this usually simplify things, some session expiration related options may not
 work as expected if other applications that write to the same directory have
 short max lifetime settings.