Ignore '/docs' on some GH actions, give docs its own action (#10949)

* ignore docs on several actions, give docs its own action

* Random doc change to see if the new action runs.

* umm... not paths-ignore, paths!

* eof fix

* enabling typescript checking on docs

docs/src/pages/404.jsx

@@ -25,7 +25,7 @@ const NotFoundPage = () => (
   <Layout>
     <SEO title="404: Not found" />
     <h1>NOT FOUND</h1>
-    <p>You just hit a route that does not exist... the sadness.</p>
+    <p>Sorry, you've requested a page that does not exist.</p>
   </Layout>
 );