Editing 'notebooks' with relative paths in Snakefile causes TypeError

[bhjolly]

Snakemake version
6.10.0
mamba create -n snakemake -c conda-forge bioconda::snakemake=6.10

Describe the bug
When using --edit-notebook with a Snakefile with a relative notebook path, a TypeError is raised when Snakemake tries to turn that into an absolute path. It looks like the 'basedir' variable type has changed but snakemake/notebook.py was not updated to reflect this.

Logs

Traceback (most recent call last):
  File "/Users/benjolly/miniconda3/envs/snakemake/lib/python3.9/site-packages/snakemake/executors/__init__.py", line 593, in _callback
    raise ex
  File "/Users/benjolly/miniconda3/envs/snakemake/lib/python3.9/concurrent/futures/thread.py", line 52, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/Users/benjolly/miniconda3/envs/snakemake/lib/python3.9/site-packages/snakemake/executors/__init__.py", line 579, in cached_or_run
    run_func(*args)
  File "/Users/benjolly/miniconda3/envs/snakemake/lib/python3.9/site-packages/snakemake/executors/__init__.py", line 2461, in run_wrapper
    raise ex
  File "/Users/benjolly/miniconda3/envs/snakemake/lib/python3.9/site-packages/snakemake/executors/__init__.py", line 2418, in run_wrapper
    run(
  File "/Users/benjolly/Documents/arsa-beech/arsa-beech-analysis/workflow/Snakefile", line 253, in __rule_seed_corr
  File "/Users/benjolly/miniconda3/envs/snakemake/lib/python3.9/site-packages/snakemake/notebook.py", line 233, in notebook
    local_path = os.path.join(basedir, path)
  File "/Users/benjolly/miniconda3/envs/snakemake/lib/python3.9/posixpath.py", line 76, in join
    a = os.fspath(a)
TypeError: expected str, bytes or os.PathLike object, not LocalSourceFile

Minimal example

rule all:
    input:
        "../results/graph.eps"
rule graph:
    output:
        "../results/graph.eps"
    notebook:
        "./notebooks/test.py.ipynb"

then
snakemake --cores 1 --edit-notebook ../results/graph.eps
(obviously need a working Jupyter environment as well)

Additional context