mention __version__ in the docs

mention version in the docs
febe845c · Christoph Groth · 6e7165cb · febe845c
Commit febe845c authored 11 years ago by Christoph Groth
--- a/doc/source/reference/kwant.rst
+++ b/doc/source/reference/kwant.rst
@@ -43,3 +43,7 @@ From `kwant.solvers.default`
   ldos
   smatrix
   wave_function
+
+Version information
+-------------------
+The version of Kwant is available under the name ``__version__``.