create cross-references in docstring (#1083)

* create cross-references in docstring

* add typing alias

Author: njzjz

doc/conf.py

@@ -220,6 +220,13 @@ def setup(app):
     ), 
     "ase": ("https://wiki.fysik.dtu.dk/ase/", None),
 }
+numpydoc_xref_param_type = True
+
+
+numpydoc_xref_aliases = {}
+import typing
+for typing_type in typing.__all__:
+    numpydoc_xref_aliases[typing_type] = "typing.%s" % typing_type
 
 # -- Options for HTML output -------------------------------------------------