Log each old backup as it is removed

Removing old backups can take minutes on a slow drive; logging each one with
its position (e.g. "(1/3)") shows that the backup is still progressing.

tests/test_local.py

@@ -140,6 +140,15 @@ class TestRsync:
 
         assert backups(out) == remaining
 
+    def test_removal_logged(self, src: Path, out: Path, caplog: pytest.LogCaptureFixture) -> None:
+        for _ in range(3):
+            assert run_backup(out, [str(src)]) == 0
+
+        assert run_backup(out, [str(src)], keep=0) == 0
+        assert 'Removing backup 2026-10-14_10-00-00 (1/3)...' in caplog.text
+        assert 'Removing backup 2026-10-14_12-00-00 (3/3)...' in caplog.text
+        assert 'Removed 3 backups' in caplog.text
+
     def test_remove_before(self, src: Path, out: Path) -> None:
         assert run_backup(out, [str(src)]) == 0
         assert run_backup(out, [str(src)], keep=0, remove_before=True) == 0