pyproject.toml

vfs: simplify the `abstractvfs.rename()` implementation

PyCharm was yapping about `util.rename()` not returning anything, because it is
typed to return `None`, but the value was captured and returned after calling
`_avoidambig()`.  Instead, drop all of that, unconditionally rename, and then
call `_avoidambig()` if appropriate.

While we're here, convert the ersatz ternary operator into a modern one to help
pytype.  When a variable is initialized the old way, pytype tends to assign the
type of the LHS of the `and`.  In this case, that's a bool, and it will get
confused that bool doesn't have a `stat` attribute once this method gets more
type annotations.  (Currently it thinks the `checkambig` arg is `Any`, so it
doesn't care.)

[build-system]
requires = ["setuptools", "wheel"]

[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true