Make some further edits to the changes in #1886

src/ch15-06-reference-cycles.md

@@ -64,15 +64,16 @@ moment, we’ll get this output:
 {{#include ../listings/ch15-smart-pointers/listing-15-26/output.txt}}
 ```
 
-The reference count of the `Rc<List>` instances in both `a` and `b` are 2
-after we change the list in `a` to point to `b`. At the end of `main`, Rust
-drops `b` which decreases the reference count of the `b` `Rc<List>` instance 
-by 1. However, the `b` `Rc<List>` can not be collected, because its reference
-count is 1, not 0. Then Rust drops `a` which decreases the reference count of
-the `a` `Rc<List>` instance by 1. This instance can not be collected either,
-because its count is 1, since the uncollected `b` `Rc<List>` instance still
-refers to it. The memory allocated to the list will remain uncollected forever.
-To visualize this reference cycle, we’ve created a diagram in Figure 15-4.
+The reference count of the `Rc<List>` instances in both `a` and `b` are 2 after
+we change the list in `a` to point to `b`. At the end of `main`, Rust drops the
+variable `b`, which decreases the reference count of the `Rc<List>` instance
+from 2 to 1. The memory that `Rc<List>` has on the heap won’t be dropped at
+this point, because its reference count is 1, not 0. Then Rust drops `a`, which
+decreases the reference count of the `a` `Rc<List>` instance from 2 to 1 as
+well. This instance's memory can’t be dropped either, because the other
+`Rc<List>` instance still refers to it. The memory allocated to the list will
+remain uncollected forever. To visualize this reference cycle, we’ve created a
+diagram in Figure 15-4.
 
 <img alt="Reference cycle of lists" src="img/trpl15-04.svg" class="center" />