Make clean command clean more stuff

Using gitignore as reference.
Is ‘/coverage’ still actually created by something?

Also making a tiny nitpick in gitignore.
diff --git a/.gitignore b/.gitignore
index f28d081..7ed21a4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 *.d.ts
-!/packages/**/@types/**/*.d.ts
+!/packages/**/src/**/*.d.ts
 *.d.ts.map
 .nyc_output
 coverage
diff --git a/package.json b/package.json
index 6ff42e2..85dfe58 100644
--- a/package.json
+++ b/package.json
@@ -19,7 +19,7 @@
     "build:js": "lerna exec --parallel -- babel -d lib -s -x .ts --env-name production --root-mode upward src",
     "build:misc": "lerna exec --parallel -- cp ../../DISCLAIMER-WIP ../../LICENSE ../../NOTICE ../../README.md .",
     "build:types": "tsc --build",
-    "clean": "tsc --build --clean && lerna exec -- rimraf DISCLAIMER-WIP LICENSE NOTICE README.md lib && rimraf docs",
+    "clean": "tsc --build --clean && lerna exec -- rimraf DISCLAIMER-WIP LICENSE NOTICE README.md lib && rimraf .nyc_output coverage docs web/dist *.tsbuildinfo",
     "docs": "tsc --build && typedoc",
     "lint": "eslint .",
     "prepublishOnly": "yarn run build",