Add stub for toml (#2355)

See https://github.com/uiri/toml/issues/178

third_party/2and3/toml.pyi

@@ -0,0 +1,24 @@
+from typing import Any, IO, List, Mapping, MutableMapping, Optional, Protocol, Text, Type, Union
+import datetime
+import sys
+
+if sys.version_info >= (3, 4):
+    import pathlib
+    if sys.version_info >= (3, 6):
+        import os
+        _PathLike = Union[Text, pathlib.PurePath, os.PathLike]
+    else:
+        _PathLike = Union[Text, pathlib.PurePath]
+else:
+    _PathLike = Text
+
+class _Writable(Protocol):
+    def write(self, obj: str) -> Any: ...
+
+class TomlDecodeError(Exception): ...
+
+def load(f: Union[_PathLike, List[Text], IO[str]], _dict: Type[MutableMapping[str, Any]] = ...) -> MutableMapping[str, Any]: ...
+def loads(s: Text, _dict: Type[MutableMapping[str, Any]] = ...) -> MutableMapping[str, Any]: ...
+
+def dump(o: Mapping[str, Any], f: _Writable) -> str: ...
+def dumps(o: Mapping[str, Any]) -> str: ...