Fix spelling of "optimize" in comment (#786)

connect.go

@@ -424,7 +424,7 @@ func receiveUnaryMessage[T any](conn receiveConn, initializer maybeInitializer,
 	}
 	// In a well-formed stream, the one message must be the only content in the body.
 	// To verify that it is well-formed, try to read another message from the stream.
-	// TODO: optimise this second receive: ideally do it w/out allocation, w/out
+	// TODO: optimize this second receive: ideally do it w/out allocation, w/out
 	//       fully reading next message (if one is present), and w/out trying to
 	//       actually unmarshal the bytes)
 	var msg2 T