fix: keep the text of unchanged Recalbox elements

Every <bios> element the model held was rendered again, so attribute order, alignment, a line break inside md5 and the case of a digest changed in 222 elements that stated the same thing. The diff deleted 451 lines for 136 corrections. An element whose attributes say what Recalbox wrote now keeps Recalbox's own text: 175 lines, the corrections.

tests/test_exporters.py

@@ -1764,5 +1764,34 @@ class BatoceraNotesStayWithTheirItem(unittest.TestCase):
         self.assertEqual(trailing, {("bios/bk0010.zip", "two.rom"): "# tail"})
 
 
+class RecalboxKeepsUnchangedText(unittest.TestCase):
+    """Every element the model held was re-rendered: attribute order,
+    alignment, line breaks inside md5 and digest case changed in 222
+    elements that said the same thing, 180 lines of diff nobody was told of."""
+
+    def test_an_element_that_says_the_same_keeps_its_text(self):
+        scraped = {"systems": {"sinclair-zxspectrum": {
+            "native_id": "zxspectrum",
+            "files": [{
+                "name": "128p-0.rom", "destination": "fuse/128p-0.rom",
+                "native_system": "zxspectrum", "native_name": "Pentagon",
+                "native_path": "fuse/128p-0.rom", "md5": "a" * 32,
+                "core": "libretro/fuse", "required": True,
+            }],
+        }}}
+        written = f'    <bios path="fuse/128p-0.rom"    md5="{"A" * 32}"\n          core="libretro/fuse" />'
+        original = (
+            '<?xml version="1.0" encoding="UTF-8"?>\n<biosList>\n'
+            '  <system fullname="Pentagon" platform="zxspectrum">\n'
+            f"{written}\n"
+            "  </system>\n</biosList>\n"
+        )
+        systems, report = build_native_model({"systems": {}}, scraped)
+        produced = discover_exporters()["recalbox"]().render(
+            systems, report, {"es_bios.xml": original}, None
+        )["es_bios.xml"]
+        self.assertIn(written, produced)
+
+
 if __name__ == "__main__":
     unittest.main()