feat: leaf_paths promoted to root

dol/__init__.py

@@ -158,6 +158,7 @@ def ihead(store, n=1):
 
 from dol.paths import (
     flatten_dict,  # flatten a nested Mapping, getting a dict
+    leaf_paths,  # get the paths to the leaves of a Mapping
     KeyTemplate,  # express strings, tuples, and dict keys from a string template
     mk_relative_path_store,  # transform path store into relative path store
     KeyPath,  # a class to represent a path to a key