files: reduce duplication in display of file entries Avoid special casing of the 'parent directory' link (..) by extracting some logic to a helper function. This avoids duplication. A subsequent commit will make changes to this logic and by introducing this helper function we only need to change in one place.

# requirements.txt file for use as "pip install -r requirements.txt" as a
# readthedocs compatible alternative to "pip install -e ." which is a working
# alternative to "setup.py develop" which doesn't work with Mercurial 3.7
.