title: "\S+?@\S+" and "\S+@\S+" give same output in regular expressions
body: <p>The following two regularexpressions give the same output in python 3.7.
  "+?" is supposed to be non-greedy </p>
  
  <pre><code>re.findall("\S+?@\S+?","From stephen.marquard@uct.ac.za Sat Jan  5 09:14:16 2008")
  re.findall("\S+@\S+","From stephen.marquard@uct.ac.za Sat Jan  5 09:14:16 2008")
  </code></pre>
  
  <p>Both of these give the same output as:</p>
  
  <pre><code> ['stephen.marquard@uct.ac.za']
  </code></pre>