fix(doc): replace invalid Hook names in doc comment with BeforeInvocationEvent & AfterInvocationEvent (#782)

Co-authored-by: deepyes02 <deepesh.dhakal@digitalwallet.co.jp>

Author: deepyes02

src/strands/hooks/__init__.py

@@ -8,17 +8,17 @@
 Example Usage:
     ```python
     from strands.hooks import HookProvider, HookRegistry
-    from strands.hooks.events import StartRequestEvent, EndRequestEvent
+    from strands.hooks.events import BeforeInvocationEvent, AfterInvocationEvent
 
     class LoggingHooks(HookProvider):
         def register_hooks(self, registry: HookRegistry) -> None:
-            registry.add_callback(StartRequestEvent, self.log_start)
-            registry.add_callback(EndRequestEvent, self.log_end)
+            registry.add_callback(BeforeInvocationEvent, self.log_start)
+            registry.add_callback(AfterInvocationEvent, self.log_end)
 
-        def log_start(self, event: StartRequestEvent) -> None:
+        def log_start(self, event: BeforeInvocationEvent) -> None:
             print(f"Request started for {event.agent.name}")
 
-        def log_end(self, event: EndRequestEvent) -> None:
+        def log_end(self, event: AfterInvocationEvent) -> None:
             print(f"Request completed for {event.agent.name}")
 
     # Use with agent