Backslash escape for underscores in Markdown docstrings

[brettcannon]

Environment data

• VS Code version:
• Python Extension version: 2018.2.0-beta
• Python Version:
• OS and version:

Actual behavior

Expected behavior

For EXPECTED_DIR to not escape the _.

Steps to reproduce:

def fixtures_dir(request):
    """Return the test fixtures directory under `FIXTURES_DIR`.

    Example::

        from conftest import BASE_DIR

        def test_something(fixtures_dir):
            assert fixtures_dir.strpath == BASE_DIR + '/some/path'

    :rtype: py.path.LocalPath
    """