After final improvements to the official formatter implementation,
this commit now performs the first treewide reformat of Nix files using it.
This is part of the implementation of RFC 166.
Only "inactive" files are reformatted, meaning only files that
aren't being touched by any PR with activity in the past 2 months.
This is to avoid conflicts for PRs that might soon be merged.
Later we can do a full treewide reformat to get the rest,
which should not cause as many conflicts.
A CI check has already been running for some time to ensure that new and
already-formatted files are formatted, so the files being reformatted here
should also stay formatted.
This commit was automatically created and can be verified using
nix-build a08b3a4d19.tar.gz \
--argstr baseRev b32a094368
result/bin/apply-formatting $NIXPKGS_PATH
JUPYTER_PATH can be used to provide additional plugins for jupyter to
use. Currently, JUPYTER_PATH is being unconditionally overridden, so
extensions are not found, e.g:
```
$ JUPYTER_PATH="path to dir with labextensions/@jupyter-widgets" jupyter labextension list 2>&1 | grep widgets
```
Instead of setting JUPYTER_PATH, prepend to it, so JUPYTER_PATH will be
respected:
```
$ JUPYTER_PATH="path to dir with labextensions/@jupyter-widgets" jupyter labextension list 2>&1 | grep widgets
@jupyter-widgets/jupyterlab-manager v5.0.13 enabled OK (python, jupyterlab_widgets)
```
