title: Where are the in-the-box problem matchers defined?
body: <p>I would like to see the source for these problem matcher, but can not find them in the vscode repo. What am I missing? Thanks!</p>
  <p><a href="https://code.visualstudio.com/docs/editor/tasks#_processing-task-output-with-problem-matchers" rel="nofollow noreferrer">https://code.visualstudio.com/docs/editor/tasks#_processing-task-output-with-problem-matchers</a></p>
  <p>Note: To me this doesn't seem like the appropriate place to be asking a question like this, but that's what the visualstudio.com/docs site said to do.</p>