Include receiver name in its string representation

The string representation of a receiver is used in logging, and
without this, it is impossible to identify which receiver is meant,
from looking at the logs.

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

src/frequenz/channels/_broadcast.py

@@ -515,7 +515,7 @@ def close(self) -> None:
 
     def __str__(self) -> str:
         """Return a string representation of this receiver."""
-        return f"{self._channel}:{type(self).__name__}"
+        return f"{self._channel}:{type(self).__name__}:{self._name}"
 
     def __repr__(self) -> str:
         """Return a string representation of this receiver."""