Missed a defaultable in comments

src/compiler/types.ts

@@ -2178,7 +2178,7 @@ namespace ts {
 
         // 'NotNarrowable' types are types where narrowing reverts to the original type, rather than actually narrow.
         // This is never really correct - you can _always_ narrow to an intersection with that type, _but_ we keep
-        // Void as the only defaultable type, since it's a non-value type construct (representing a lack of a value)
+        // Void as the only non-narrowable type, since it's a non-value type construct (representing a lack of a value)
         // and, generally speaking, narrowing `void` should fail in some way, as it is nonsensical. (`void` narrowing
         // to `void & T`, in a structural sense, is just narrowing to T, which we wouldn't allow under normal rules)
         NotNarrowable = Void,