gh-150942: Improve performance of csv reader by using _PyList_AppendT… - #155957

Description

This PR improves the performance of the csv module's reader by replacing standard PyList_Append calls with the internal _PyList_AppendTakeRef stealing method.

When parsing CSV fields, the C extension previously appended the parsed field to a list and subsequently decremented the reference count of the field. By using the new stealing methods, we avoid the overhead of an unnecessary incref/decref pair and slightly simplify the C implementation.

Changes:

• Included "pycore_list.h" in Modules/_csv.c.
• Replaced PyList_Append followed by Py_DECREF with _PyList_AppendTakeRef in the parse_save_field function.
• Added the corresponding NEWS blurb.

• Issue: Improve performance by using reference stealing methods #150942