docs(hardlink): address review feedback on doc comments and error attrs

- Trim InodeKey doc to a single line (remove over-explanation)
- Restore doc style for SizeConflictError and NumberOfLinksConflictError
  with `ino`, `dev`, and `nlink` links to MetadataExt methods
- Rephrase Reflection guarantee as "pair of an inode number and a device
  number"
- Remove unnecessary #[error(not(source))] on DuplicatedInode tuple
  variant (derive_more only auto-assumes source for single-field
  variants)

https://claude.ai/code/session_01QP9wZyoZcGmJsEsA66ZRok

Author: claude

src/hardlink/hardlink_list.rs

@@ -21,11 +21,6 @@ use pipe_trait::Pipe;
 use std::path::Path;
 
 /// Internal key used to uniquely identify an inode across all filesystems.
-///
-/// Hardlinks cannot span filesystems, so including the device number prevents
-/// false deduplication of files from different filesystems that happen to share
-/// the same inode number. Both du-dust and dua-cli track `(device, inode)` pairs
-/// for the same reason.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
 struct InodeKey {
     /// Inode number within the device.
@@ -78,7 +73,10 @@ impl<Size> HardlinkList<Size> {
     }
 }
 
-/// Error that occurs when a different size was detected for the same inode.
+/// Error that occurs when a different size was detected for the same [`ino`] and [`dev`].
+///
+/// [`ino`]: std::os::unix::fs::MetadataExt::ino
+/// [`dev`]: std::os::unix::fs::MetadataExt::dev
 #[derive(Debug, Display, Error)]
 #[cfg_attr(test, derive(PartialEq, Eq))]
 #[display(bound(Size: Debug))]
@@ -90,7 +88,11 @@ pub struct SizeConflictError<Size> {
     pub detected: Size,
 }
 
-/// Error that occurs when a different number of links was detected for the same inode.
+/// Error that occurs when a different [`nlink`] was detected for the same [`ino`] and [`dev`].
+///
+/// [`nlink`]: std::os::unix::fs::MetadataExt::nlink
+/// [`ino`]: std::os::unix::fs::MetadataExt::ino
+/// [`dev`]: std::os::unix::fs::MetadataExt::dev
 #[derive(Debug, Display, Error)]
 #[cfg_attr(test, derive(PartialEq, Eq))]
 #[display(

src/hardlink/hardlink_list/reflection.rs

@@ -12,7 +12,7 @@ use serde::{Deserialize, Serialize};
 /// internal content.
 ///
 /// **Guarantees:**
-/// * Every `(device, inode)` pair is unique.
+/// * Every pair of an inode number and a device number is unique.
 /// * The internal list is always sorted by inode numbers (with device number as tie-breaker).
 ///
 /// **Equality:** `Reflection` implements `PartialEq` and `Eq` traits.
@@ -113,10 +113,7 @@ impl<Size> From<HardlinkList<Size>> for Reflection<Size> {
 pub enum ConversionError {
     /// When the source has a duplicated `(inode, device)` pair.
     #[display("Inode {_0} on device {_1} is duplicated")]
-    DuplicatedInode(
-        #[error(not(source))] InodeNumber,
-        #[error(not(source))] DeviceNumber,
-    ),
+    DuplicatedInode(InodeNumber, DeviceNumber),
 }
 
 impl ConversionError {