Minor tweak

Author: javiereguiluz

components/config/definition.rst

@@ -873,6 +873,5 @@ Otherwise the result is a clean array of configuration values::
 
 .. caution::
 
-    When processing the configuration tree, the processor assumes the top level 
-    array key is already stripped off. If you want a root name, you should
-    add it to your tree builder as an array node.
+    When processing the configuration tree, the processor assumes that the top
+    level array key (which matches the extension name) is already stripped off.