minor #22170 Fix a typo in a routing example (laurentbardin)

This PR was merged into the 7.4 branch.

Discussion
----------

 Fix a typo in a routing example

Fix a small typo in a YAML example of the routing documentation.

Based off of `7.4` because that's where it was introduced (i.e. prior branches don't have that typo).

Commits
-------

2587abc Fix a typo in a routing example

Author: javiereguiluz

routing.rst

@@ -1769,7 +1769,7 @@ when importing the routes.
 
         # config/routes.yaml
         controllers:
-            resource: routing.controllerss
+            resource: routing.controllers
             # this is added to the beginning of all imported route URLs
             prefix: '/blog'
             # this is added to the beginning of all imported route names