Update proposals/NNNN-global-actor-isolated-types-usability.md

Co-authored-by: John McCall <[email protected]>

Author: simanerush

proposals/NNNN-global-actor-isolated-types-usability.md

@@ -50,7 +50,7 @@ func test() {
 
 Requiring both a global actor attribute and `@Sendable` creates an unfortunate pile-up of attributes, and it would be better to infer `@Sendable` from the global actor attribute.
 
-Because a globally-isolated closure cannot be called concurrently, it's safe for it to capture non-`Sendable` values even if it's implicitly `@Sendable`.  Such values just need to be transferred to the global actor's region (if they aren't there already).  This also applies to closures that are isolated to a specific actor reference.
+Because a globally-isolated closure cannot be called concurrently, it's safe for it to capture non-`Sendable` values even if it's implicitly `@Sendable`.  Such values just need to be transferred to the global actor's region (if they aren't there already).  The same logic also applies to closures that are isolated to a specific actor reference, although it isn't currently possible to write such a closure in a context that isn't isolated to that actor.
 
 
 Finally, the current diagnostic for a global-actor-isolated subclass of a non-isolated superclass is too restrictive: