link to json issue

README.md

@@ -9,7 +9,7 @@ and is fast (on the order of 1ms of CPU time per token
 Following grammar formats are supported:
 - `llguidance` - [internal (JSON-based) format](./parser/src/api.rs)
 - regular expressions (following Rust regex crate [syntax](https://docs.rs/regex/latest/regex/#syntax))
-- a large subset of JSON schemas
+- a large subset of JSON schemas (but see [issue](https://github.com/microsoft/llguidance/issues/44))
 - context-free grammars in (a [subset](./parser/src/lark/README.md) of) [Lark](https://github.com/lark-parser/lark) format
 
 The internal format is most powerful and can be generated by the following libraries: