Reference to scoped label must quoted

doc/user/markdown.md

@@ -405,6 +405,7 @@ GFM will recognize the following:
 | label by ID                     | `~123`                     | `namespace/project~123`                 | `project~123`                  |
 | one-word label by name          | `~bug`                     | `namespace/project~bug`                 | `project~bug`                  |
 | multi-word label by name        | `~"feature request"`       | `namespace/project~"feature request"`   | `project~"feature request"`    |
+| scoped label by name            | `~"priority::high"`        | `namespace/project~"priority::high"`    | `project~"priority::high"`     |
 | project milestone by ID         | `%123`                     | `namespace/project%123`                 | `project%123`                  |
 | one-word milestone by name      | `%v1.23`                   | `namespace/project%v1.23`               | `project%v1.23`                |
 | multi-word milestone by name    | `%"release candidate"`     | `namespace/project%"release candidate"` | `project%"release candidate"`  |