clean code with clippy

src/law/mod.rs

@@ -140,6 +140,12 @@ impl PartialEq for LawBuilder {
     }
 }
 
+impl Default for LawBuilder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl LawBuilder {
     /// Creates a new law builder. Adds classifier for known law texts.
     pub fn new() -> Self {