Issue #25523: Backported a-to-an corrections.
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index 9ab724a..1269bf6 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -1307,7 +1307,7 @@
     int op                      /* Operation: Py_EQ, Py_NE, Py_GT, etc. */
     );
 
-/* Apply a argument tuple or dictionary to a format string and return
+/* Apply an argument tuple or dictionary to a format string and return
    the resulting Unicode string. */
 
 PyAPI_FUNC(PyObject *) PyUnicode_Format(