Documentation fixes for openfermion.ops._interaction_operator (#503)
Documentation fixes for openfermion.ops._interaction_operator (#503)

The documentation for the interationOperator appearted to be
missing some math mode specifiers.  I've added those. The
mathematical form for the operator is no properly displayed
and the format for the one and two body integrals in the that
show up in the documentation agree with that formatting.
quantumlib/OpenFermion,kevinsung/OpenFermion,jarrodmcc/OpenFermion,kevinsung/OpenFermion,quantumlib/OpenFermion,kevinsung/OpenFermion,quantumlib/OpenFermion,jarrodmcc/OpenFermion