Trigger focus event after reload (#4931)

- Indexes restart after reload, so same-index item was not seen as new
- With --id-nth, compare by key. No event if focused item keeps its key.
- Skip focus check while track is blocked
- Document that binding reload to focus can loop

Close #4930

CHANGELOG.md

@@ -6,6 +6,9 @@ CHANGELOG
 - Fixed `--gap-line` cutting a grapheme cluster when filling the last cells of the line (#4920)
 - Fixed an escape sequence fzf does not recognize being partly consumed, which leaked the rest into the query (#4926)
 - Fixed a key lost when it arrived in the same read as an escape sequence
+- Fixed `focus` event not triggered after `reload` when the new item is at the same position as the previous one (#4930)
+    - With `--id-nth`, the event is not triggered if the focus moves directly from an item to another item with the same key
+    - A `focus` binding that runs `reload` now triggers itself again after each reload, unless `--id-nth` is set and the key does not change
 
 0.74.4
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