Mark <wbr> as self-closing

Author: twm

html5lib/constants.py

@@ -572,7 +572,8 @@
     "col",
     "input",
     "source",
-    "track"
+    "track",
+    "wbr",
 ])
 
 cdataElements = frozenset(['title', 'textarea'])

html5lib/tests/test_sanitizer.py

@@ -61,7 +61,7 @@ def test_data_uri_disallowed_type():
 
 def test_wbr_allowed():
     sanitized = sanitize_html('<wbr>')
-    expected = '<wbr>'
+    expected = '<wbr/>'
     assert expected == sanitized