fixup! Explain the Receiver.close() method in the user guide

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

Author: shsms

src/frequenz/channels/_receiver.py

@@ -125,9 +125,11 @@
 
 # Closing receivers
 
-To deal with situations where data from a particular stream is no-longer required,
-receivers offer a [`close()`][frequenz.channels.Receiver.close] method that can be used
-to stop it from receiving new messages.
+When a particular stream of data is no-longer required, it is a good practice to close
+the receiver to free up resources. This is especially important in applications that are
+repeatedly creating new receivers.  The
+[`Receiver.close()`][frequenz.channels.Receiver.close] method can be used for this
+purpose.
 
 After `close()` is called, we can still receive messages that are in the receiver's
 buffer, but as soon as the receiver's buffer has been drained, trying to receive further