## Summary
This PR fixes a silent failure that manifested itself in
https://github.com/astral-sh/ruff-vscode/issues/238. In short, if the
user provided invalid arguments to Ruff in the VS Code extension (like
`"ruff.args": ["a"]`), then we generated something like the following
command:
```console
/path/to/ruff --force-exclude --no-cache --no-fix --format json - --fix a --stdin-filename /path/to/file.py
```
Since this contains both `-` and `a` as the "input files", Ruff would
treat this as if we're linting the files names `-` and `a`, rather than
linting standard input.
This PR modifies out standard input detection to force standard input
when `--stdin-filename` is present, or at least one file is `-`. (We
then warn and ignore the others.)
1d2d015bc5