title: Syntax highlighting not working for Python in VS Code with type annotations after reformatting
body: <p>I'm trying to get Visual Studio Code to format (the colours not the layout) Python code with type annotations (hinting). It's failing to do so for the following code:</p>
  
  <pre><code>from typing import Iterator
  
  # return math.factorial(x)
  def fib(n: int) -&gt; Iterator[int]:
      a, b = 0, 1
      while a &lt; n:
          yield a
          a, b = b, a + b        
  
  """
  This function checks whether a string is a palindrome.
  s - The string to check.
  """
  def is_palindrome(s: str) -&gt; bool:
      return s == s[::-1]
  
  """
  This function compares two strings of word letters and returns the percentage match.
  
  p_string1 - The first letters to compare.
  p_string2 - The second letters to compare.
  """
  def compare_letters(p_string1: str, p_string2: str) -&gt; float:
      return 1.0
  </code></pre>
  
  <p>I'm using <code>"python.formatting.provider": "black"</code> but I also tried <code>autopep8</code> and <code>yapf</code>. They all seem to fail in the same way, by getting it all mixed up after the type annotations.</p>
  
  <p>When I go to the <code>black</code> website and paste the code into the Black Playground it works fine though.</p>
  
  <p>I have upgraded using <code>python -m pip install --upgrade black</code> and it is showing the same version (black-19.10b0) as the Black Playground, so not sure where this is Visual Studio Code issue or a me issue.</p>
  
  <p>I am using <code>WinPython 3.7.1 (v3.7.1:260ec2c36a, Oct 20 2018, 14:57:15) [MSC v.1915 64 bit (AMD64)] on win32</code>.</p>
  
  <p>Not really sure what to log a bug against with all this linting, formatting (colour/layout), Python parsing, etc.</p>
  
  <p>Has anyone had any success with formatting Python type annotations in Visual Studio Code and what settings are you using?</p>
  
  <p>UPDATE: This does not happen when I run with <code>code --disable-extensions</code>. Does anyone know how I can disable extensions selectively in order to find out which one is causing the issue?</p>