LibWeb: Add BodyInit union type

Author: https://github.com/linusg
Commit: 8f5620b5d9
Pull-request: https://github.com/SerenityOS/serenity/pull/15323
Reviewed-by: https://github.com/davidot ✅
Reviewed-by: https://github.com/kennethmyhra ✅

Userland/Libraries/LibWeb/Fetch/BodyInit.h

@@ -16,6 +16,9 @@ namespace Web::Fetch {
 // https://fetch.spec.whatwg.org/#typedefdef-xmlhttprequestbodyinit
 using XMLHttpRequestBodyInit = Variant<JS::Handle<FileAPI::Blob>, JS::Handle<JS::Object>, JS::Handle<URL::URLSearchParams>, String>;
 
+// https://fetch.spec.whatwg.org/#bodyinit
+using BodyInit = Variant<JS::Handle<Streams::ReadableStream>, JS::Handle<FileAPI::Blob>, JS::Handle<JS::Object>, JS::Handle<URL::URLSearchParams>, String>;
+
 ErrorOr<Infrastructure::BodyWithType> extract_body(JS::Realm&, XMLHttpRequestBodyInit const&);
 
 }