add instructions for how to suppress warnings

Author: jreiberkyle

noxfile.py

@@ -43,6 +43,8 @@ def test(session):
 
     options = session.posargs
     # -W=error raises pytest warnings to errors so they are caught by CI
+    # to exclude some warnings, see
+    # https://docs.python.org/3/library/warnings.html#temporarily-suppressing-warnings
     session.run('pytest', '--ignore', 'examples/', '-v', '-W=error', *options)