bpo-36974: rename _FastCallKeywords -> _Vectorcall (GH-13653)

diff --git a/Tools/gdb/libpython.py b/Tools/gdb/libpython.py
index d49546f..93f720a 100755
--- a/Tools/gdb/libpython.py
+++ b/Tools/gdb/libpython.py
@@ -1564,7 +1564,7 @@
             return False
 
         if caller in ('_PyCFunction_FastCallDict',
-                      '_PyCFunction_FastCallKeywords',
+                      '_PyCFunction_Vectorcall',
                       'cfunction_call_varargs'):
             arg_name = 'func'
             # Within that frame: