GDScript: Allow string keys on Lua-style dictionaries

Which is useful when the key isn't a valid identifier, such as keys with
spaces or numeric keys.

modules/gdscript/gdscript_compiler.cpp

@@ -440,7 +440,7 @@ GDScriptCodeGenerator::Address GDScriptCompiler::_parse_expression(CodeGen &code
 						break;
 					case GDScriptParser::DictionaryNode::LUA_TABLE:
 						// Lua-style: key is an identifier interpreted as StringName.
-						StringName key = static_cast<const GDScriptParser::IdentifierNode *>(dn->elements[i].key)->name;
+						StringName key = dn->elements[i].key->reduced_value.operator StringName();
 						element = codegen.add_constant(key);
 						break;
 				}