[interop][SwiftToCxx] update status doc for static property support

Author: hyp

docs/CppInteroperability/CppInteroperabilityStatus.md

@@ -188,6 +188,7 @@ This status table describes which of the following Swift language features have
 | Getter accessors               | Yes, via `get<name>`. Boolean properties that start with `is` or `has` are remapped directly to a getter method using their original name                         |
 | Setter accessors               | Yes, via `set<name>`                                     |
 | Mutation accessors             | No                                                       |
+| Static property accessors      | Yes                         |
 
 **Generics**