refactor(core): change _processedSpec to experimental_processedSpec (#…

…1077)

* refactor: change to experimental_specProcessed

* Update src/core/gosling-component.tsx

Co-authored-by: SEHI L'YI <sehilyi@gmail.com>

* fix: change name

---------

Co-authored-by: SEHI L'YI <sehilyi@gmail.com>

src/core/gosling-component.tsx

@@ -26,7 +26,8 @@ export interface UrlToFetchOptions {
 type CompiledCallbackFn = (
     goslingSpec: gosling.GoslingSpec,
     higlassSpec: gosling.HiGlassSpec,
-    _additionalData: { _processedSpec: gosling.GoslingSpec }
+    /** @deprecated This is an experimental object that is not intended for production usage. */
+    experimental: { _processedSpec: gosling.GoslingSpec }
 ) => void;
 
 export interface GoslingCompProps {