Fix-up indentation of sample code blocks for namedtuple mthod definitions.
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index fc2b802..f024843 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -724,7 +724,7 @@
 
    Class method that makes a new instance from an existing sequence or iterable.
 
-.. doctest::
+   .. doctest::
 
       >>> t = [11, 22]
       >>> Point._make(t)
@@ -740,9 +740,7 @@
 .. method:: somenamedtuple._replace(kwargs)
 
    Return a new instance of the named tuple replacing specified fields with new
-   values:
-
-::
+   values::
 
       >>> p = Point(x=11, y=22)
       >>> p._replace(x=33)
@@ -756,7 +754,7 @@
    Tuple of strings listing the field names.  Useful for introspection
    and for creating new named tuple types from existing named tuples.
 
-.. doctest::
+   .. doctest::
 
       >>> p._fields            # view the field names
       ('x', 'y')