Add changelog entry

Author: daxpedda

CHANGELOG.md

@@ -20,6 +20,10 @@
 * Add bindings to `Date.to_locale_time_string_with_options`.
   [#4384](https://github.com/rustwasm/wasm-bindgen/pull/4384)
 
+* `#[wasm_bindgen]` now correctly applies `#[cfg(...)]`s in `struct`s.
+  [#4351](https://github.com/rustwasm/wasm-bindgen/pull/4351)
+
+
 ### Changed
 
 * Optional parameters are now typed as `T | undefined | null` to reflect the actual JS behavior.