Resolve clippy::unnecessary_debug_formatting warning

```
error: unnecessary `Debug` formatting in `format!` args
   --> src/main.rs:673:53
    |
673 |             path.to_str().with_context(|| format!("{path:?} contains invalid utf-8 data"))?,
    |                                                     ^^^^
    |
    = help: use `Display` formatting and change this to `path.display()`
    = note: switching to `Display` formatting will change how the value is shown; escaped characters will no longer be escaped and surrounding quotes will be removed
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_debug_formatting
    = note: `-D clippy::unnecessary-debug-formatting` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::unnecessary_debug_formatting)]`
```

Author: taiki-e

src/main.rs

@@ -669,9 +669,9 @@ fn merge_profraw(cx: &Context) -> Result<()> {
     }
     let mut input_files = String::new();
     for path in profraw_files {
-        input_files.push_str(
-            path.to_str().with_context(|| format!("{path:?} contains invalid utf-8 data"))?,
-        );
+        input_files.push_str(path.to_str().with_context(|| {
+            format!("{} ({:?}) contains invalid utf-8 data", path.display(), path.as_os_str())
+        })?);
         input_files.push('\n');
     }
     let input_files_path = &cx.ws.target_dir.join(format!("{}-profraw-list", cx.ws.name));