adjust debug assertion to count blobs and executables (#1224)

Fixes #1224.

The intention was to check for blobs, which can also be executable,
even though the expectation ended up only allowing blobs, not executables.

This is now fixed. Fortunately this was only an issue in debug builds.

Author: Byron

gix-diff/src/rewrites/tracker.rs

@@ -468,9 +468,8 @@ fn find_match<'a, T: Change>(
     } else {
         let mut has_new = false;
         let percentage = percentage.expect("it's set to something below 1.0 and we assured this");
-        debug_assert_eq!(
-            item.change.entry_mode().kind(),
-            EntryKind::Blob,
+        debug_assert!(
+            item_mode.is_blob(),
             "symlinks are matched exactly, and trees aren't used here"
         );