Brought back a sentence about supposed inefficiency.

Author: michal-czardybon

src/doc/trpl/ownership.md

@@ -132,7 +132,8 @@ after we’ve done the move.
 [sh]: the-stack-and-the-heap.html
 
 It’s also important to note that optimizations may remove the actual copy of
-the bytes on the stack, depending on circumstances.
+the bytes on the stack, depending on circumstances. So it may not be as
+inefficient as it initially seems.
 
 ## `Copy` types