tests/cpydiff: Indent workaround code snippet so it formats correctly.

Author: dpgeorge

tests/cpydiff/types_exception_subclassinit.py

@@ -4,9 +4,9 @@
 cause: Subclassing native classes is not fully supported in MicroPython.
 workaround: Call using ``super()`` instead::
 
-class A(Exception):
-    def __init__(self):
-        super().__init__()
+    class A(Exception):
+        def __init__(self):
+            super().__init__()
 """
 class A(Exception):
     def __init__(self):