Stop executing two code samples in inject's docstring as tests

They're actually meant to be just for human use here. Executing them
will fail as the Dependency is not defined.

injector/__init__.py

@@ -1190,21 +1190,21 @@ def inject(constructor_or_class):
     >>> a = Injector(configure).get(A)
     [123, 'Bob']
 
-    As a convenience one can decorate a class itself:
+    As a convenience one can decorate a class itself::
 
-    >>> @inject
-    ... class B:
-    ...     def __init__(self, dependency: Dependency):
-    ...         self.dependency = dependency
+        @inject
+        class B:
+            def __init__(self, dependency: Dependency):
+                self.dependency = dependency
 
     This is equivalent to decorating its constructor. In particular this provides integration with
     `dataclasses <https://docs.python.org/3/library/dataclasses.html>`_ (the order of decorator
-    application is important here):
+    application is important here)::
 
-    >>> @inject
-    ... @dataclass
-    ... class C:
-    ...     dependency: Dependency
+        @inject
+        @dataclass
+        class C:
+            dependency: Dependency
 
     .. note::