Replace issue_* with issue-* in test filenames for consistency

[fee1-dead]

No description provided.

[calebcartwright]

this is something that's been brought up a few times over the years, but of which i remain ambivalent on how to proceed.

consistency is indeed the desirable characteristic that I'm all for; my struggle is with snake vs kebab case. I've often wondered if there were any established convention on the tests side of things, but find myself leaning towards snake case over other conventions (perhaps just mental carry over from conventions around app/test modules that get imported).

rustc seems to have a blend, as does clippy (though ratio leans heavily towards snake). cargo seems to be heavily (perhaps ubiquitously) snake.

are you suggesting kebab because we have significantly more kebab than snake files, or is there a convention/standard/etc. you're aware of that prefers kebab?

[fee1-dead]

As far as I'm concerned, rustc's ui tests prefer kebab case, and that can help distinguish different names in ui tests, e.g. some-test-related-to-some_feature_name.rs. rustc features, and in this case rustfmt's configuration options have snake case names, so using something like issue-1234-option_name.rs could help distinguishing them in test names. This is why I think kebab case is preferred, but it doesn't seem to be documented anywhere. At least for issues, rustc keeps them kebab case.