Sigh, fix Python 3 syntax

Python 3 doesn't allow the ur'' prefix for raw unicode strings.
We want a unicode string here so that we get a unicode regexp,
so drop the r and do the escaping explicitly (the regexp in question
is pretty simple, fortunately).

pokedex/tests/test_database_sanity.py

@@ -96,7 +96,7 @@ def test_default_forms(session):
         elif num_default_pokemon > 1:
             pytest.fail("species %s has %d default pokemon" % (species.name, num_default_pokemon))
 
-ROUTE_RE = re.compile(ur'route-\d+')
+ROUTE_RE = re.compile(u'route-\\d+')
 
 def test_location_identifiers(session):
     """Check that location identifiers for some common locations are prefixed