bpo-42670: Fix a missing word in the itertools.product() docs (GH-23823) (GH-23824)

diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index 3de66c934928157752b388d79b8871f37422f3e3..85f4928ce84fbef85378176a4d4774ccb71e6c74 100644 (file)
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -565,7 +565,7 @@ 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])