Fix error message to use the Python name instead of the C name
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index d91c99a..ea038de 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -1091,7 +1091,7 @@
PyDoc_STRVAR(exit_doc,
"exit()\n\
-(PyThread_exit_thread() is an obsolete synonym)\n\
+(exit_thread() is an obsolete synonym)\n\
\n\
This is synonymous to ``raise SystemExit''. It will cause the current\n\
thread to exit silently unless the exception is caught.");