gh-142440: apply context to x, not v, in _decimal_Context_apply_impl

V is not even defined here.

Author: AZero13

Misc/NEWS.d/next/Core_and_Builtins/2025-12-08-18-40-17.gh-issue-142438.tH-Y16.rst

@@ -0,0 +1,2 @@
+Fix _decimal builds configured with EXTRA_FUNCTIONALITY by correcting the
+Context.apply wrapper to pass the right argument.

Modules/_decimal/_decimal.c

@@ -6990,7 +6990,7 @@ _decimal_Context_apply_impl(PyObject *context, PyTypeObject *cls,
                             PyObject *x)
 /*[clinic end generated code: output=f8a7142d47ad4ff3 input=388e66ca82733516]*/
 {
-    return _decimal_Context__apply(context, v);
+    return _decimal_Context__apply(context, x);
 }
 #endif