Better log canonicalization errors (#32030)

Based on
https://github.com/zed-industries/zed/issues/18673#issuecomment-2933025951

Adds an anyhow error context with the path used for canonicalization
(also, explicitly mention path at the place from the comment).

Release Notes:

- N/A

crates/worktree/src/worktree.rs

@@ -3948,7 +3948,7 @@ impl BackgroundScanner {
         let root_canonical_path = match self.fs.canonicalize(root_path.as_path()).await {
             Ok(path) => SanitizedPath::from(path),
             Err(err) => {
-                log::error!("failed to canonicalize root path: {}", err);
+                log::error!("failed to canonicalize root path {root_path:?}: {err}");
                 return true;
             }
         };