Fix error messages on Windows

src/loading/fs.rs

@@ -121,10 +121,9 @@ impl Loader for FsLoader {
     }
 
     fn resolve(&self, path: &Path) -> io::Result<FileHash> {
-        let file = File::open(path)?;
-        let meta = file.metadata()?;
+        let meta = fs::metadata(path)?;
         if meta.is_file() {
-            let handle = Handle::from_file(file)?;
+            let handle = Handle::from_path(path)?;
             Ok(FileHash(fxhash::hash64(&handle)))
         } else {
             Err(io::ErrorKind::NotFound.into())

tests/typeset.rs

@@ -316,7 +316,11 @@ fn test_part(
     let mut errors: Vec<_> = errors
         .into_iter()
         .filter(|error| error.span.source() == id)
-        .map(|error| (ctx.sources.range(error.span), error.message))
+        .map(|error| {
+            let range = ctx.sources.range(error.span);
+            let msg = error.message.replace("\\", "/");
+            (range, msg)
+        })
         .collect();
 
     errors.sort_by_key(|error| error.0.start);