Problem:
Built-in diff mode (nvim -d) does not support directory diffing
as required by git difftool -d. This makes it difficult to compare
entire directories, detect renames, and navigate changes efficiently.
Solution:
Add a DiffTool plugin and command that enables side-by-side diffing of
files and directories in Neovim. The plugin supports rename detection,
highlights changes in the quickfix list, and provides a user command for
easy invocation. This allows proper integration with git difftool -d for
directory comparison.
Example git config:
```ini
[diff]
tool = nvim_difftool
[difftool "nvim_difftool"]
cmd = nvim -c "packadd nvim.difftool" -c "DiffTool $LOCAL $REMOTE"
```
Signed-off-by: Tomas Slusny <slusnucky@gmail.com>
Co-authored-by: Phạm Bình An <111893501+brianhuster@users.noreply.github.com>
Co-authored-by: Justin M. Keyes <justinkz@gmail.com>
