Auto merge of #38473 - zackmdavis:issue_kebab, r=sanxiyn

prefer hyphens in test files named after issue numbers

We have a lot of tests with filenames honoring particular issues by
number. Typically, these are called issue-${issue_no}.rs (note the
hyphen):

```
$ find . -regextype posix-egrep -regex '.*/issue-[0-9]*.rs' | wc
   1289    1289   35935
```

We also had a much smaller number of files that are like this, but don't
have a hyphen in between the substring `issue` and the number:

```
$ find . -regextype posix-egrep -regex '.*/issue[0-9]*.rs'
./debuginfo/issue14411.rs
./debuginfo/issue12886.rs
./debuginfo/issue13213.rs
./debuginfo/issue22656.rs
./debuginfo/issue7712.rs
./compile-fail/issue32829.rs
./run-pass/issue24353.rs
./run-pass/issue34796.rs
./run-pass/issue18173.rs
./run-pass/issue22346.rs
./run-pass/auxiliary/issue13507.rs
./run-pass/issue26127.rs
./run-pass/issue22008.rs
./run-pass/issue34569.rs
./run-pass/issue29927.rs
./run-pass/issue36260.rs
```

Some would argue that the inconsistency is æsthetically displeasing,
hence this trivial patch. (Note that run-pass/auxiliary/issue13507.rs
has an excuse; it's `use`d in run-pass/issue-13507-2.rs; the matter of
there being two different compile-fail tests with different name
conventions for issue no. 32829 is also neglected here for the sake of
keeping this trivial cleanup patch as trivial as possible for ease of
review.)