Fix markup

pep-0422.txt

@@ -268,6 +268,7 @@ Order preserving classes
 ------------------------
 
 ::
+
     class OrderedClass(namespace=collections.OrderedDict()):
         a = 1
         b = 2
@@ -278,6 +279,7 @@ Prepopulated namespaces
 -----------------------
 
 ::
+
     seed_data = dict(a=1, b=2, c=3)
     class PrepopulatedClass(namespace=seed_data.copy()):
         pass
@@ -287,6 +289,7 @@ Cloning a prototype class
 -------------------------
 
 ::
+
     class NewClass(namespace=Prototype.__dict__.copy()):
         pass
 
@@ -295,6 +298,7 @@ Defining an extensible class
 ----------------------------
 
 ::
+
     class Extensible:
         namespace = locals()