Fix cursor movement on shortened deletes and refactor

backend/reconcile/tests/example_document.rs

@@ -65,7 +65,7 @@ impl ExampleDocument {
         for (i, cursor) in text.cursors.iter().enumerate() {
             assert!(
                 cursor.char_index <= result.len(), // equals in case of insert at the end
-                "Cursor index out of bounds: {} > {}",
+                "Cursor index out of bounds: {} > {} when testing for '{result}'",
                 cursor.char_index,
                 result.len()
             );

backend/reconcile/tests/examples/various.yml

@@ -67,7 +67,7 @@ expected: market| placemarket|space
 parent: A B C D
 left: A X B D|
 right: A B Y|
-expected: A X B Y||
+expected: A X B |Y|
 
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