allow passing '-' as filename, print reformatted setup.cfg to stdout

[seanbreckenridge]

Was trying to set this up to autoformat my setup.cfg files in neovim, and the easiest way to do that (with the plugin I use) is to be able to read from STDIN/write back to STDOUT which then replaces the contents of the buffer. I ended up just wrapping it in a script like:

#!/usr/bin/env bash
set -e
tfile="$(mktemp -t setup.cfg.XXXXXX -p "$(pwd)")"
cat >"$tfile"
setup-cfg-fmt "$@" "$tfile" >&2 || true
cat "$tfile"
command rm -f "$tfile"

and that works, but would be nice to be able to avoid the tempfile.

So, proposed feature is to be able to call this with like setup-cfg-fmt - <setup.cfg, and it prints the formatted setup.cfg to stdout

If you're ok with adding this, I can make a PR

[asottile]

tbh I'd rather not carry the complexity and you've already got a working solution

[seanbreckenridge]

yeah, fair enough -- I only format a setup.cfg once in a while anyways, so this is fine as a solution

after reading through the code would infect a bunch of things because of _adjacent_filename

For anyone else trying to do this, should note that you should make the setup.cfg tempfile in the same directory as the setup.cfg, so it can pick up readme/license changes