Implement stdin-stdout operation with '-' file argument

[AndydeCleyre]

This works well in my casual testing, and can even be used in combination with regular file arguments. But I haven't written a formal test for it yet, so I'm marking this as a draft.

It makes sure to write the stdin to stdout if there's a problem formatting/encoding/decoding, and if no formatting is necessary. This ensures it doesn't delete content when used as one step in a pipeline of successive formatters and linters.

[AndydeCleyre]

I have pylint checks failing locally, but for files I haven't changed.

[bwhmather]

Might be worth adding something to find_python_files to prevent it from searching directories named '-'.

I think I agree that it makes sense to allow mixing '-' with other arguments.

[bwhmather]

Looks good. I recon fix find_python_files to skip '-' then I'll merge and bake a new release.

if the content is already ssort-ed, the output is empty. When used as a step in a multiple-formatter pipeline, this leads to deleting the content.

Lol.

[coveralls]

Pull Request Test Coverage Report for Build 11673472686

Details

• 25 of 30 (83.33%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.1%) to 98.132%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/ssort/_main.py	24	29	82.76%

Files with Coverage Reduction	New Missed Lines	%
src/ssort/_main.py	1	92.0%

Totals
Change from base Build 11673464849:	-0.1%
Covered Lines:	1366
Relevant Lines:	1392

---

💛 - Coveralls

[bwhmather]

I have pylint checks failing locally, but for files I haven't changed.

Yup. Not your fault. pylint not pinned. This is something we've chatted about fixing. Not the fastest moving project so stuff like this sadly inevitable. Have raised #120.

[bwhmather]

Thank you very much. I've pushed v0.14.0 to pypi with this change.