handle multiple udiffs inside a single fenced block

tests/test_udiff.py

@@ -68,6 +68,52 @@ Some text...
         self.assertEqual(edit[0], "dir name with spaces/file.txt")
         self.assertEqual(edit[1], ["-Original\n", "+Modified\n"])
 
+    def test_find_multi_diffs(self):
+        content = """
+To implement the `--check-update` option, I will make the following changes:
+
+1. Add the `--check-update` argument to the argument parser in `aider/main.py`.
+2. Modify the `check_version` function in `aider/versioncheck.py` to return a boolean indicating whether an update is available.
+3. Use the returned value from `check_version` in `aider/main.py` to set the exit status code when `--check-update` is used.
+
+Here are the diffs for those changes:
+
+```diff
+--- aider/versioncheck.py
++++ aider/versioncheck.py
+@@ ... @@
+     except Exception as err:
+         print_cmd(f"Error checking pypi for new version: {err}")
++        return False
+
+--- aider/main.py
++++ aider/main.py
+@@ ... @@
+     other_group.add_argument(
+         "--version",
+         action="version",
+         version=f"%(prog)s {__version__}",
+         help="Show the version number and exit",
+     )
++    other_group.add_argument(
++        "--check-update",
++        action="store_true",
++        help="Check for updates and return status in the exit code",
++        default=False,
++    )
+     other_group.add_argument(
+         "--apply",
+         metavar="FILE",
+```
+
+These changes will add the `--check-update` option to the command-line interface and use the `check_version` function to determine if an update is available, exiting with status code `0` if no update is available and `1` if an update is available.
+"""  # noqa: E501
+
+        edits = find_diffs(content)
+        dump(edits)
+        self.assertEqual(len(edits), 2)
+        self.assertEqual(len(edits[0][1]), 3)
+
 
 if __name__ == "__main__":
     unittest.main()