Update current limitations doc

CURRENT_LIMITATIONS.md

@@ -1,21 +1,7 @@
 # Current Limitations
 
-## Required for 1.0
-- [x] Interface type support
-- [x] Nested input object support
-- [x] Union type support
-- [x] `mutation` or `subscription` operation support
-- [x] Nullable field support
-- [x] Variable definition support
-- [x] Rewrite `Result` and `Variable` types
-- [x] Type-level testing
-- [x] Default unknown scalars to `string`'s
-- [ ] Fix nested variable extraction
-- [ ] Dynamic selector building (using Proxy's)
-- [ ] Restricing `Selection`'s in selector function returns
-- [ ] Finish rewriting unit tests
-- [ ] Field alias support
-- [ ] Directive support
-- [ ] Custom scalar support yet (e.g no `Date` objects), limited to JS built-ins (custom scalars default to `string`'s)
-- [ ] Named fragments
-- [ ] Documentation
+- [`const` assertions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-4.html#const-assertions) required for abstract type selections
+- No field alias support
+- No named fragment support
+- No client directive support
+- No nested input object variable support