add a link to the “returned values” subsection

Author: glessard

proposals/NNNN-non-escapable.md

@@ -103,8 +103,9 @@ func f() -> NotEscapable {
 ```
 
 **Note**:
+The section ["Returned nonescapable values require lifetime dependency"](#Returns) explains the implications for how you must write initializers.
 
-Without `~Escapable`, the default for any type is to be escapable.  Since `~Escapable` suppresses a capability, you cannot put this in an extension.
+Without `~Escapable`, the default for any type is to be escapable.  Since `~Escapable` suppresses a capability, you cannot declare it with an extension.
 
 ```swift
 // Example: Escapable by default
@@ -195,7 +196,7 @@ enum NonescapableEnum: ~Escapable {
 }
 ```
 
-#### Returned nonescapable values require lifetime dependency
+#### <a name="Returns"></a>Returned nonescapable values require lifetime dependency
 
 As mentioned earlier, a simple return of a nonescapable value is not permitted:
 ```swift