refactor(service_container): refactoring on wording

Author: Guikingone

service_container/injection_types.rst

@@ -103,8 +103,8 @@ then extending it and overriding the constructor becomes problematic.
 Immutable-setter Injection
 --------------------------
 
-Another possible injection in to use a method which return ``static``,
-this approach allow you to make a service immutable::
+Another possible injection in to use a method which return a separate instance
+by cloning the original service, this approach allow you to make a service immutable::
 
     // ...
 
@@ -179,7 +179,7 @@ which allow the container to return the newly created service:
     for the container to be capable of registering the method.
 
 This approach is useful if you need to configure your service according to your needs,
-so, what are the advantages?
+so, here's the advantages of immutable-setters:
 
 * Immutable setters works with optional dependencies, this way, if you don't need
   a dependency, the setter don't need to be called.