minor #11378 use max 2 blank lines (OskarStark)

This PR was merged into the 3.4 branch.

Discussion
----------

use max 2 blank lines

<!--

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
-------

d3829a1 use max 2 blank lines

Author: javiereguiluz

cache.rst

@@ -316,7 +316,6 @@ For advanced configurations it could sometimes be useful to use a pool as an ada
         ]);
 
 
-
 Creating a Cache Chain
 ----------------------