Add missing new line

Author: colesbury

Doc/howto/free-threading-python.rst

@@ -116,4 +116,4 @@ compared to the default GIL-enabled build.  In 3.13, this overhead is about
 40% on the `pyperformance <https://pyperformance.readthedocs.io/>`_ suite.
 Programs that spend most of the their time in C extensions or I/O will see
 less of an impact.  This overhead is expected to be reduced in the upcoming
-3.14 release.
+3.14 release.