fix: count a recalbox element kept as written

An element whose md5 the truth contradicts without naming another is
written back whole. It was counted as an entry the format cannot keep.
It now counts as kept, and the md5 it keeps is named as withheld.

tests/test_exporters.py

@@ -1169,6 +1169,32 @@ class RecalboxExport(unittest.TestCase):
             [("cdimono1.zip", False, True)],
         )
 
+    def test_an_element_kept_as_written_is_not_counted_lost(self):
+        """The truth takes the entry on sha1 and size and names no md5: the
+        element is written back whole, and the run counted it a platform
+        entry the format cannot keep."""
+        scraped = {"systems": {"x": {"native_id": "x", "files": [{
+            "name": "a.bin", "destination": "x/a.bin", "md5": "a" * 32, "size": 100,
+            "native_system": "x", "core": "libretro/foo", "required": True,
+        }]}}}
+        truth = {"systems": {"x": {"files": [{
+            "name": "a.bin", "path": "x/a.bin", "sha1": "b" * 40, "size": 200,
+            "required": True, "_cores": ["foo"],
+        }]}}}
+        element = f'    <bios path="x/a.bin" md5="{"a" * 32}" core="libretro/foo" />'
+        original = (
+            '<?xml version="1.0" encoding="UTF-8"?>\n<biosList>\n'
+            f'  <system fullname="X" platform="x">\n{element}\n  </system>\n</biosList>\n'
+        )
+        systems, report = build_native_model(truth, scraped)
+        exporter = discover_exporters()["recalbox"]()
+        produced = exporter.render(systems, report, {"es_bios.xml": original}, None)
+        self.assertIn(element, produced["es_bios.xml"])
+        fe = next(fe for s in systems.values() for fe in s.files)
+        self.assertTrue(exporter.lands(fe))
+        self.assertEqual(landed_changes(exporter, systems).records, [])
+        self.assertEqual(len(exporter.withheld()), 1)
+
     def test_a_truncated_export_is_reported(self):
         exporter, systems, _ = self._render()
         empty = {