Add signature for new (as of Python 3.7) breakpoint

Author: eriknw

toolz/_signatures.py

@@ -237,6 +237,8 @@
 
 if PY3:  # pragma: py2 no cover
     module_info[builtins].update(
+        breakpoint=[
+            lambda *args, **kws: None],
         bytes=[
             lambda: None,
             lambda int: None,

toolz/tests/test_inspect_args.py

@@ -402,7 +402,6 @@ def add_blacklist(mod, attr):
             blacklist.add(getattr(mod, attr))
 
     add_blacklist(builtins, 'basestring')
-    add_blacklist(builtins, 'breakpoint')
     add_blacklist(builtins, 'NoneType')
     add_blacklist(builtins, '__metaclass__')
     add_blacklist(builtins, 'sequenceiterator')