clean up documentation for BPM bond styles

[jibril-b-coulibaly]

Summary

Form changes on the BPM documentation

Related Issue(s)

1. break/no remaining
2. consistency of descriptions with keyword yes / no values
3. 4. other minor form changes

Author(s)

Jibril B. Coulibaly, Sandia National Laboratories (jibril.coulibaly@gmail.com)

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

OK

Implementation Notes

N/A

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

Further Information, Files, and Links

I think further aesthetic changes could be useful, up to @jtclemm :

1. detail the formulation of the tangent force and torques in the bpm_rotational docs
2. Use capital F letters for forces in bpm/rotational, for consistency with bpm/spring
3. use \cdot instead of \bullet to describe the dot product in damping force
4. use present term rather than "will be" when describing the effects of options