format: rustfmt the Storage conversions

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

crates/clawhdf5-format/src/object_header.rs

@@ -385,13 +385,13 @@ impl ObjectHeader {
         }
 
         let chunk0_msg_start = pos;
-        let chunk0_msg_end = abs(pos)
-            .checked_add(chunk0_size)
-            .ok_or(FormatError::UnexpectedEof {
+        let Some(chunk0_abs_end) = abs(pos).checked_add(chunk0_size) else {
+            return Err(FormatError::UnexpectedEof {
                 expected: usize::MAX,
                 available: file_len,
-            })?
-            - base;
+            });
+        };
+        let chunk0_msg_end = chunk0_abs_end - base;
 
         // The whole first chunk, prefix to checksum, in one read (its
         // bounds check is the one on the checksum's 4 bytes).
@@ -1364,7 +1364,11 @@ mod tests {
                     let want = ObjectHeader::parse(&f, at, 8, 8);
                     let storage = CountingStorage::new(f.clone());
                     let got = ObjectHeader::parse_in(&storage, at as u64, 8, 8);
-                    assert_eq!(format!("{got:?}"), format!("{want:?}"), "at {at}, cut {cut}");
+                    assert_eq!(
+                        format!("{got:?}"),
+                        format!("{want:?}"),
+                        "at {at}, cut {cut}"
+                    );
                 }
             }
         }