Update test_outline.py

Trying to force a rerun: change American spelling to British

Author: jsa34

tests/feature/test_outline.py

@@ -222,7 +222,7 @@ def _(string):
 
 
 def test_forward_slash_in_params(pytester):
-    """Test parametrized scenario when the parameter contains a slash, such in a URL."""
+    """Test parametrised scenario when the parameter contains a slash, such in a URL."""
 
     pytester.makefile(
         ".feature",