fixup! Improve the file_watcher module documentation

Author: llucax

src/frequenz/channels/file_watcher.py

@@ -31,7 +31,7 @@
 
 
 class EventType(Enum):
-    """The types of changes that can be observed."""
+    """The types of file events that can be observed."""
 
     CREATE = Change.added
     """The file was created."""
@@ -87,7 +87,6 @@ class FileWatcher(Receiver[Event]):
         ```python
         import asyncio
 
-        from frequenz.channels import select, selected_from
         from frequenz.channels.file_watcher import EventType, FileWatcher
 
         PATH = "/tmp/test.txt"
@@ -106,11 +105,9 @@ async def main() -> None:
                 file.write("Hello, world!")
             async with asyncio.TaskGroup() as group:
                 group.create_task(update_file())
-                async for selected in select(file_watcher):
-                    if selected_from(selected, file_watcher):
-                        event = selected.value
-                        print(f"File {event.path}: {event.type.name}")
-                        break
+                async for event in file_watcher:
+                    print(f"File {event.path}: {event.type.name}")
+                    break
 
 
         asyncio.run(main())