style(lib): address clippy code style warnings

* Remove unnecessary return statements.

* Combine identical `match` arms.

* Collapse nested conditional.

* Use `assert_ne` where applicable.

* Lifetime elision.

src/uri.rs

@@ -80,7 +80,7 @@ impl Uri {
             })
         } else if (s.contains("/") || s.contains("?")) && !s.contains("://") {
             // last possibility is authority-form, above are illegal characters
-            return Err(UriError(ErrorKind::Malformed))
+            Err(UriError(ErrorKind::Malformed))
         } else {
             // authority-form
             let len = s.len();