Word processors track revisions, but such tools are restrictive and won't work for markup languages. Cloud tools for collaboration such as Docs exist, including some for LaTeX, but requiring connectivity while editing is a non-starter for me. I would even be happy with a custom LaTeX solution; the features I desire for text VC are similar to those for code:
- Non-proprietary, application-agnostic, platform-independent FOSS
- Revision history: see what has changed.
- Revert: undo changes back to forever.
- Lock-free: work in parallel, which requires...
- Pain-free merge: help resolve conflicting commits.
- Distributed and offline editing: no active (server) connections
- External contributions: integrate changes made outside of VC