code: public Collection<TypedDependency> typedDependenciesCollapsedTree() {
      List<TypedDependency> tdl = typedDependencies(false);
      collapseDependenciesTree(tdl);
      return tdl;
    }
docs: Get the typed dependencies after mostly collapsing them, but keep a tree
  structure.  In order to do this, the code does:
  <ol>
  <li> no relative clause processing
  <li> no xsubj relations
  <li> no propagation of conjuncts
  </ol>
  
  @return collapsed dependencies keeping a tree structure