fixes #22932; treats closure iterators as pointers (#22934)

fixes #22932
follow up https://github.com/nim-lang/Nim/pull/21629

---------

Co-authored-by: Nickolay Bukreyev <SirNickolas@users.noreply.github.com>
(cherry picked from commit 0dc3513613)

lib/pure/options.nim

@@ -81,7 +81,7 @@ when defined(nimPreviewSlimSystem):
 
 when (NimMajor, NimMinor) >= (1, 1):
   type
-    SomePointer = ref | ptr | pointer | proc
+    SomePointer = ref | ptr | pointer | proc | iterator {.closure.}
 else:
   type
     SomePointer = ref | ptr | pointer
@@ -89,7 +89,7 @@ else:
 type
   Option*[T] = object
     ## An optional type that may or may not contain a value of type `T`.
-    ## When `T` is a a pointer type (`ptr`, `pointer`, `ref` or `proc`),
+    ## When `T` is a a pointer type (`ptr`, `pointer`, `ref`, `proc` or `iterator {.closure.}`),
     ## `none(T)` is represented as `nil`.
     when T is SomePointer:
       val: T

tests/stdlib/toptions.nim

@@ -196,6 +196,12 @@ proc main() =
         doAssert x.isNone
         doAssert $x == "none(cstring)"
 
-
 static: main()
 main()
+
+when not defined(js):
+  block: # bug #22932
+    var it = iterator: int {.closure.} = discard
+    doAssert it.option.isSome # Passes.
+    it = nil
+    doAssert it.option.isNone # Passes.