wmlunits: Do not list abilities without name attributes

This reflects the in-game behavior, which is used to build compound
abilities with only one help entry.

data/tools/unit_tree/html_output.py

@@ -737,11 +737,13 @@ class HTMLOutput:
                     continue
                 already[id] = True
                 name = T(ability, "name")
-                if not name:
-                    name = id
                 if not name:
                     name = ability.name.decode("utf8")
-                anames.append(name)
+                # Only add abilities with a label, since those that lack one
+                # are normally hidden in the game and used to implement more
+                # complex ones.
+                if name:
+                    anames.append(name)
         return anames
 
     def get_recursive_attacks(self, this_unit):