Update IMDv3 support details for GROMACS, NAMD, and LAMMPS

- state for each engine if they support concurrent connections
- minor markup/link reformatting
- moved information  from MDAnalysis/mdanalysis#4923 to here

Author: orbeckst

docs/source/usage.rst

@@ -25,6 +25,8 @@ Specific IMDv3 options were added to GROMACS, as documented in the
 GROMACS User Guide `Molecular dynamics parameters (.mdp options)`_ under
 *Interactive Molecular Dynamics (IMD)*.
 
+GROMACS does *not* support multiple concurrent connections to the same IMD port.
+
 In GROMACS, you will know that the simulation is ready and waiting for the
 IMDClient when this line is printed to the terminal:
 
@@ -44,7 +46,9 @@ NAMD
 ----
 The IMDv3 protocol has been implementaed in NAMD and will be made available through the
 official NAMD release in the near future. It is currently available as a part of the
-official NAMD GitLab repository - https://gitlab.com/tcbgUIUC/namd.
+official NAMD GitLab repository https://gitlab.com/tcbgUIUC/namd .
+
+NAMD **does** support multiple concurrent connections to the same IMD port.
 
 To use IMDv3 with NAMD, add the following lines to your NAMD configuration file:
 
@@ -75,10 +79,12 @@ You are now ready to connect to the simulation engine with the IMDClient.
 
 LAMMPS
 ------
-The IMDv3 protocol is part of the official LAMMPS distribution since ``patch_4Feb2025``.
-It is available in the LAMMPS source code repository - https://github.com/lammps/lammps.
-Information on using IMDv3 with LAMMPS can be found in the LAMMPS documentation
-- https://docs.lammps.org/fix_imd.html
+The IMDv3 protocol is part of the official LAMMPS distribution since **patch_4Feb2025**.
+It is available in the LAMMPS source code repository https://github.com/lammps/lammps.
+Information on using IMDv3 with LAMMPS can be found in the LAMMPS documentation for 
+`fix_imd`_.
+
+LAMMPS does *not* support multiple concurrent connections to the same IMD port.
 
 To use IMDv3 with LAMMPS, add the following lines to your LAMMPS input script:
 
@@ -95,6 +101,8 @@ following terminal message:
 
 You are now ready to connect to the simulation engine with a client.
 
+.. _`fix_imd`: https://docs.lammps.org/fix_imd.html
+
 Using IMDClient
 ^^^^^^^^^^^^^^^