Auto merge of #41745 - oli-obk:diagnostics, r=jonathandturner

Remove need for &format!(...) or &&"" dances in `span_label` calls

These were always a thorn in my eye. Note that this will monomorphize to two impls, one for `String` and one for `&str`. But I think that cost is worth the ergonomics at the call sites that can be seen throughout this PR.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index 6b1267d89b6..528d903b8b0 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -2412,7 +2412,7 @@ mod tests {
 
         let tmpdir = tmpdir();
         let unicode = tmpdir.path();
-        let unicode = unicode.join(&format!("test-각丁ー再见"));
+        let unicode = unicode.join("test-각丁ー再见");
         check!(fs::create_dir(&unicode));
         assert!(unicode.exists());
         assert!(!Path::new("test/unicode-bogus-path-각丁ー再见").exists());