add iterutils.redundant to the docs

boltons/iterutils.py

@@ -709,10 +709,10 @@ def unique_iter(src, key=None):
 def redundant(src, key=None, groups=False):
     """The complement of :func:`unique()`.
 
-    By default returns non-unique values as a list of the *first*
+    By default returns non-unique/duplicate values as a list of the
-    redundant value in *src*. Pass ``groups=True`` to get groups of
+    *first* redundant value in *src*. Pass ``groups=True`` to get
-    all values with redundancies, ordered by position of the first
+    groups of all values with redundancies, ordered by position of the
-    redundant value. This is useful in conjunction with some
+    first redundant value. This is useful in conjunction with some
     normalizing *key* function.
 
     >>> redundant([1, 2, 3, 4])

docs/iterutils.rst

@@ -24,6 +24,7 @@ present in the standard library.
 .. autofunction:: windowed_iter
 .. autofunction:: unique
 .. autofunction:: unique_iter
+.. autofunction:: redundant
 
 Stripping and splitting
 -----------------------