[hooks] Fix a "typo" in docstring

hooks.py

@@ -151,7 +151,7 @@ class partial_match_rtype(PartialPredicateMixIn, hook.match_rtype):
 
 
 class LinkResourceToDatasetHook(hook.Hook):
-    """Create a CKAN dataset upon link of a resource-like entity to a
+    """Create a CKAN resource upon link of a resource-like entity to a
     dataset-like entity.
 
     Actual implementations should at least fill the `rtype` attribute.