Add bindings for PyUnstable 3.14 APIs (#5828)

* add PyUnstable 3.14 bindings

* add changelog entry

* add PyUnstable 3.15 bindings

Author: luxedo

newsfragments/5828.added.md

@@ -0,0 +1 @@
+Added FFI wrappers for the following PyUnstable APIs available in Python 3.14: `PyUnstable_Object_IsUniquelyReferenced`, `PyUnstable_Object_IsUniquelyReferencedTemporary`, `PyUnstable_EnableTryIncref`, `PyUnstable_TryIncref`

pyo3-ffi/src/cpython/object.rs

@@ -398,3 +398,23 @@ extern "C" {
 // skipped PyRefTracer
 // skipped PyRefTracer_SetTracer
 // skipped PyRefTracer_GetTracer
+
+#[cfg(Py_3_14)]
+extern "C" {
+    // skipped PyUnstable_Object_EnableDeferredRefcount
+
+    pub fn PyUnstable_Object_IsUniqueReferencedTemporary(obj: *mut PyObject) -> c_int;
+
+    // skipped PyUnstable_IsImmortal
+
+    pub fn PyUnstable_TryIncRef(obj: *mut PyObject) -> c_int;
+
+    pub fn PyUnstable_EnableTryIncRef(obj: *mut PyObject) -> c_void;
+
+    pub fn PyUnstable_Object_IsUniquelyReferenced(op: *mut PyObject) -> c_int;
+}
+
+#[cfg(Py_3_15)]
+extern "C" {
+    pub fn PyUnstable_SetImmortal(op: *mut PyObject) -> c_int;
+}