style(examples): apply ruff formatting to sample scripts

examples/get_ad.py

@@ -2,6 +2,7 @@
 
 import lbc
 
+
 def main() -> None:
     # Initialize the Leboncoin API client
     client = lbc.Client()
@@ -18,5 +19,6 @@ def main() -> None:
     # Print information about the user who posted the ad
     print("User info:", ad.user)
 
+
 if __name__ == "__main__":
     main()