Check docs and run clippy on PRs (#326)

* Check docs, clippy, test run

* test parallel CI adapted from other package; is it faster?

* Remember to download substrate

* Nightly for cargo fmt

* Standardise CI names

* fix clippy complaints

* Ensure docs are valid and export publicly accessible types

* all-targets clippy, and fix additional lint errors

* newline in ci file

tests/integration/frame/system.rs

@@ -37,7 +37,7 @@ async fn storage_account() {
         .api
         .storage()
         .system()
-        .account(alice.account_id().clone().into(), None)
+        .account(alice.account_id().clone(), None)
         .await;
     assert_matches!(account_info, Ok(_))
 }