CHANGES: mark breaking changes

CHANGES.md

@@ -1,18 +1,19 @@
 ## Unpublished
 
-- PPX: Add runtime for `result`
-  ([#13](https://github.com/melange-community/melange-json/pull/13))
-- PPX: Add `yojson` as runtime dep for the native version
-  ([#15](https://github.com/melange-community/melange-json/pull/15))
-- PPX: Rename `[@json.as]` to `[@json.name]`
-- PPX: Drop special encoding for enumeration-like variants (variants with each
+- **[breaking]** PPX: Rename `[@json.as]` to `[@json.name]`
+  ([#23](https://github.com/melange-community/melange-json/pull/23))
+- **[breaking]** PPX: Drop special encoding for enumeration-like variants (variants with each
   constructor having no arguments).
   ([#26](https://github.com/melange-community/melange-json/pull/26))
-- PPX: change JSON representation of polyvariants, make it compatible with 
+- **[breaking]** PPX: change JSON representation of polyvariants, make it compatible with 
   ppx_deriving_yojson and ppx_yojson_conv
   ([#27](https://github.com/melange-community/melange-json/pull/27))
-- PPX: Consistent use of exceptions in runtime.
+- **[breaking]** PPX: Consistent use of exceptions in runtime.
   ([#28](https://github.com/melange-community/melange-json/pull/28))
+- PPX: Add runtime for `result`
+  ([#13](https://github.com/melange-community/melange-json/pull/13))
+- PPX: Add `yojson` as runtime dep for the native version
+  ([#15](https://github.com/melange-community/melange-json/pull/15))
 - PPX: add `[@@json_string]` for deriving converters to/from JSON strings
   directly
   ([#30](https://github.com/melange-community/melange-json/pull/30))