Fixing compilation mistake, updating dev reference

src/npair_nsq.cpp

@@ -1,8 +1,8 @@
 // clang-format off
-/* ----------------------------------------------------------------------
+/* -*- c++ -*- ----------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
-   Steve Plimpton, sjplimp@sandia.gov
+   LAMMPS development team: developers@lammps.org
 
    Copyright (2003) Sandia Corporation.  Under the terms of Contract
    DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
@@ -16,6 +16,7 @@
 #include "neigh_list.h"
 #include "atom.h"
 #include "atom_vec.h"
+#include "group.h"
 #include "molecule.h"
 #include "neighbor.h"
 #include "domain.h"