Function argument hint only shows one argument, expect whole signature (and optionally docstring)

[tdaff]

Environment data

VS Code version: 1.18.0
Python Extension version: 0.8.0
Python Version: 2.7.14
OS and version: Linux, Gentoo

Actual behavior

When writing code, the popup when typing the opening bracket of a function only has one argument and no documentation information.

Expected behavior

It would be great to have the popup more like the hover window, so that I can see the whole signature and perhaps have an option to display the docstring too.

Steps to reproduce:

• Open Python file.
• Write a function name and an opening bracket

This has been brought up before in https://github.com/DonJayamanne/pythonVSCode/issues/598

[brettcannon]

Closing as a duplicate of #70