style: Make word-break: break-word behave like word-break: normal; overflow-wrap: anywhere.

Differential Revision: https://phabricator.services.mozilla.com/D21398

components/style/properties/gecko.mako.rs

@@ -1328,6 +1328,7 @@ impl Clone for ${style_struct.gecko_struct_name} {
         "TransformOrigin": impl_simple,
         "UserSelect": impl_simple,
         "url::UrlOrNone": impl_css_url,
+        "WordBreak": impl_simple,
         "ZIndex": impl_simple,
     }