Correct ABI tag for 3.15+ (FT) with Py_LIMITED_API

This should be tagged `cp315-abi3.abi3t`, not `cp315-abi3t`

Author: encukou

peps/pep-0803.rst

@@ -605,10 +605,10 @@ built with a given interpreter and ``Py_LIMITED_API`` macro:
 | ``cp315-abi3``        | 3.15+ (GIL) | 3.15               | ---                 | continued |
 +-----------------------+-------------+--------------------+---------------------+-----------+
 | ``cp315-abi3t``       | 3.15+       | ---                | 3.15                | new       |
-+                       +-------------+--------------------+---------------------+           +
-|                       | 3.15+ (FT)  | 3.15               | ---                 |           |
 +-----------------------+-------------+--------------------+---------------------+-----------+
-| ``cp315-abi3.abi3t``  | 3.15+       | 3.15               | 3.15                | new       |
+| ``cp315-abi3.abi3t``  | 3.15+ (FT)  | 3.15               | ---                 | new       |
++                       +-------------+--------------------+---------------------+           +
+|                       | 3.15+       | 3.15               | 3.15                |           |
 +-----------------------+-------------+--------------------+---------------------+-----------+