Fix typo discovered by codespell

___codespell --quiet-level=2___
```
./python-patterns/patterns/behavioral/publish_subscribe.py:68: subscirbed ==> subscribed
./python-patterns/patterns/structural/front_controller.py:30: cant ==> can't
./python-patterns/patterns/structural/front_controller.py:72: cant ==> can't
```

Author: cclauss

patterns/behavioral/publish_subscribe.py

@@ -65,7 +65,7 @@ def main():
     >>> vani.subscribe("movie")
     >>> vani.unsubscribe("movie")
 
-    # Note that no one subscirbed to `ads`
+    # Note that no one subscribed to `ads`
     # and that vani changed their mind
 
     >>> fftv.publish("cartoon")