LibIDL+IDLGenerators: Support generation of IDL partial dictionaries

Author: https://github.com/devgianlu
Commit: 348db1c445
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3117
Reviewed-by: https://github.com/ADKaster ✅

Libraries/LibIDL/Types.h

@@ -297,6 +297,7 @@ public:
     Optional<Function> named_property_deleter;
 
     HashMap<ByteString, Dictionary> dictionaries;
+    HashMap<ByteString, Vector<Dictionary>> partial_dictionaries;
     HashMap<ByteString, Enumeration> enumerations;
     HashMap<ByteString, Typedef> typedefs;
     HashMap<ByteString, Interface*> mixins;