bpo-23495: Correct the documentation for writerows() of csv Writer objects (GH-6316)

`writerows()` takes an iterable.
(cherry picked from commit a801cf16)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Doc/library/csv.rst

@@ -453,8 +453,9 @@ read CSV files (assuming they support complex numbers at all).
 
 .. method:: csvwriter.writerows(rows)
 
-   Write all the *rows* parameters (a list of *row* objects as described above) to
-   the writer's file object, formatted according to the current dialect.
+   Write all elements in *rows* (an iterable of *row* objects as described
+   above) to the writer's file object, formatted according to the current
+   dialect.
 
 Writer objects have the following public attribute: