Auto merge of #25761 - ralexstokes:master, r=steveklabnik

Typo in explanation of difference between stack and heap values.

`baz` is called at the end of a call to `bar` inside another call to `foo`.  `baz` takes a copy of the value `e` which should have a value of 9 if following the rest of the stack trace.

This PR fixes this typo and should close #25635.