Add hover for commands from LAMMPS Docs

[chappertron]

Use a similar approach to the LAMMPS vscode extension by the ThFriedrich:

1. Copy LAMMPS Docs Folder
2. Extract syntax sections, perhaps in a build script?
3. Match the fix/compute pair style and provide as a hover to the LSP Server.

The list of commands and styles could be extracted from these docs.

[chappertron]

An initial version was added in commit d99832313b21a952cd1eae311fdca9597fc220d5

This opens docs when hovering over the entire line, not just the command name or style. The next step for this is to refine to provide hover over a specific word.