Merge pull request #1826 from jeanmonod/new-enum-node-type

Add the new enum node type in 2.1

Author: weaverryan

components/config/definition.rst

@@ -100,6 +100,7 @@ node definition. Node type are available for:
 * scalar
 * boolean
 * array
+* enum (new in 2.1)
 * variable (no validation)
 
 and are created with ``node($name, $type)`` or their associated shortcut