bpo-42670: Fix a missing word in the itertools.product() docs (GH-23823)

diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index 44728b42287bce2ddbe1bc9e84b1a0d1f00313d1..612a66f25371dc5f2da5a335cb6c48c4e08c2041 100644 (file)
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -582,7 +582,7 @@ loops that truncate the stream.
 
    Before :func:`product` runs, it completely consumes the input iterables,
    keeping pools of values in memory to generate the products.  Accordingly,
-   it only useful with finite inputs.
+   it is only useful with finite inputs.
 
 .. function:: repeat(object[, times])