Update text/3519-arbitrary-self-types-v2.md

Clarify a long sentence

Co-authored-by: teor <teor@riseup.net>

Author: adetaylor

text/3519-arbitrary-self-types-v2.md

@@ -188,7 +188,7 @@ impl<T> Receiver for CustomPtr<T> {
 
 ## Recursive arbitrary receivers
 
-Receivers are recursive and therefore allowed to be nested. If type `T` implements `Receiver<Target=U>`, and type `U` implements `Receiver<Target=Self>`, `T` is a valid receiver (and so on outward). This is the behavior for the current special-cased self types (`Pin`, `Box` etc.) so as we remove the special-casing we need to retain this property.
+Receivers are recursive and therefore allowed to be nested. If type `T` implements `Receiver<Target=U>`, and type `U` implements `Receiver<Target=Self>`, `T` is a valid receiver (and so on outward). This is the behavior for the current special-cased self types (`Pin`, `Box` etc.), so as we remove the special-casing, we need to retain this property.
 
 For example, this self type is valid: