Collected small fixes and changes

[akohlmey]

Summary

This pull request combines multiple small fixes and changes.

Related Issue(s)

N/A

Author(s)

Axel Kohlmeyer, Temple U

Licensing

By submitting this pull request, I agree, that my contribution will be included in LAMMPS and redistributed under either the GNU General Public License version 2 (GPL v2) or the GNU Lesser General Public License version 2.1 (LGPL v2.1).

Backward Compatibility

N/A

Implementation Notes

The following individual changes are included:

• print a meaningful error message instead of a file-not-found error when fix qeq/reaxff is used with the "reax/c" keyword instead of the required "reaxff"
• use std::move() in a few cases to avoid redundant copies of temporaries
• whitespace and coding style updates
• silence some compiler warnings
• fix a bug in the Kokkos version of pair hybrid when some atom types have more than one pair style assigned

Post Submission Checklist

• The feature or features in this pull request is complete
• Licensing information is complete
• Corresponding author information is complete
• The source code follows the LAMMPS formatting guidelines
• Suitable new documentation files and/or updates to the existing docs are included
• The added/updated documentation is integrated and tested with the documentation build system
• The feature has been verified to work with the conventional build system
• The feature has been verified to work with the CMake based build system