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/utils/node_proc.rs

@@ -72,7 +72,7 @@ where
                 err
             );
             log::error!("{}", err);
-            return Err(err.into())
+            return Err(err)
         }
         Ok(())
     }
@@ -132,7 +132,7 @@ impl TestNodeProcessBuilder {
 
         let ws_port = if self.scan_port_range {
             let (p2p_port, http_port, ws_port) = next_open_port()
-                .ok_or("No available ports in the given port range".to_owned())?;
+                .ok_or_else(|| "No available ports in the given port range".to_owned())?;
 
             cmd.arg(format!("--port={}", p2p_port));
             cmd.arg(format!("--rpc-port={}", http_port));
@@ -169,7 +169,7 @@ impl TestNodeProcessBuilder {
                 Err(err) => {
                     if attempts < MAX_ATTEMPTS {
                         attempts += 1;
-                        wait_secs = wait_secs * 2; // backoff
+                        wait_secs *= 2; // backoff
                         continue
                     }
                     break Err(err)
@@ -187,7 +187,7 @@ impl TestNodeProcessBuilder {
                 proc.kill().map_err(|e| {
                     format!("Error killing substrate process '{}': {}", proc.id(), e)
                 })?;
-                Err(err.into())
+                Err(err)
             }
         }
     }
@@ -216,14 +216,11 @@ fn next_open_port() -> Option<(u16, u16, u16)> {
             Ordering::SeqCst,
         );
         let next = PORT.fetch_add(1, Ordering::SeqCst);
-        match TcpListener::bind(("0.0.0.0", next)) {
-            Ok(_) => {
-                ports.push(next);
-                if ports.len() == 3 {
-                    return Some((ports[0], ports[1], ports[2]))
-                }
+        if TcpListener::bind(("0.0.0.0", next)).is_ok() {
+            ports.push(next);
+            if ports.len() == 3 {
+                return Some((ports[0], ports[1], ports[2]))
             }
-            Err(_) => (),
         }
         ports_scanned += 1;
         if ports_scanned == MAX_PORTS {