altered wording

Author: divix1988

doc/book/configuring-the-service-manager.md

@@ -8,7 +8,7 @@ constructor. The following keys are:
 - `abstract_factories`: a list of abstract factories classes. An abstract
   factory is a factory that can potentially create any object, based on some
   criterias.
-- `delegators`: associative array that map key to a delegator factory key, see the [delegators documentation](delegators.md) for more details.
+- `delegators`: an associative array that maps service keys to lists of delegator factory keys, see the [delegators documentation](delegators.md) for more details.
 - `aliases`: associative array that map a key to a service key (or another alias).
 - `initializers`: a list of callable or initializers that are run whenever a service has been created.
 - `shared`: associative array that map a service name to a boolean, in order to