[docs] A small amount of copy diting of ARCOPtimization.rst.

Author: gottesmm

docs/ARCOptimization.rst

@@ -232,7 +232,8 @@ this is true. The rule for conversions is that a conversion that preserves RC
 identity must have the following properties:
 
 1. Both of its arguments must be non-trivial values with the same ownership
-   semantics (i.e. unowned, strong, weak). This means that conversions such as:
+   semantics (i.e. unowned, strong, weak). This means that the following
+   conversions do not propagate RC identity:
 
    - address_to_pointer
    - pointer_to_address