Address some issues from the core conformance suite (#4)

Also address Clippy warnings

js/ui/package.json

@@ -41,11 +41,11 @@
 		"typescript": "^4.0.3",
 		"webpack": "^5.16.0",
 		"webpack-cli": "^4.4.0",
-		"webpack-dev-server": "^3.11.2"
+		"webpack-dev-server": "^4.6.0"
 	},
 	"scripts": {
 		"build": "cross-env NODE_ENV=production webpack",
-		"dev": "webpack serve --content-base ../../static --port 9080",
+		"dev": "webpack serve --static-directory ../../static --port 9080",
 		"validate": "svelte-check"
 	},
 	"dependencies": {