Add code action to format code when there's a final new line missing

[luabud]

Ref: https://github.com/microsoft/vscode-pylint/issues/43

There are two things that needs to be done:

• [ ] Create quick fix for warning code C0304:missing-final-newline that triggers the format document action
• [ ] Add unit test

The code for the first step will be similar to the one here: https://github.com/microsoft/vscode-pylint/blob/2fae19e66aaf079c3dc190b81f913695ac65b078/bundled/tool/server.py#L243

And the unit tests will be similar to this: https://github.com/microsoft/vscode-pylint/blob/2fae19e66aaf079c3dc190b81f913695ac65b078/src/test/python_tests/test_code_actions.py#L23

[gagandeepp]

interested please assign

[gagandeepp]

@luabud @karthiknadig can you please add hacktoberfest label to this repo and issue?

[brettcannon]

@gagandeepp sorry, but we are purposefully not participating in Hacktoberfest due to multiple years of low-quality PRs because of the event.