1c6b20a5

By: ValentinHirschi <valentin.hirschi@gmail.com>

Stop tracking NNLO research artifacts

Keep the local research files while removing the directory from the Git index.
The existing ignore rule already covers this directory.

User request:
You pushed `examples/cli/epem_a_ttxh/NNLO/RESEARCH/`, remove its tracking and commit+push again.