Fix nnf.tseitin docs

Author: blyxxyz

docs/nnf.rst

@@ -43,3 +43,11 @@ nnf.amc module
    :members:
    :undoc-members:
    :show-inheritance:
+
+nnf.tseitin module
+------------------
+
+.. automodule:: nnf.tseitin
+   :members:
+   :undoc-members:
+   :show-inheritance:

nnf/tseitin.py

@@ -1,5 +1,5 @@
-"""Transformations using the well-known Tseitin encoding
-<https://en.wikipedia.org/wiki/Tseytin_transformation>
+"""Transformations using the well-known `Tseitin encoding
+<https://en.wikipedia.org/wiki/Tseytin_transformation>`_.
 
 The Tseitin transformation converts any arbitrary circuit to one in CNF in
 polynomial time/space. It does so at the cost of introducing new variables