Refactor code based on clippy suggestions

src/mt19937.rs

@@ -40,10 +40,10 @@ impl MT19937 {
     }
 
     pub fn extract_number(&mut self) -> u32 {
-        if self.index == N {
-            self.twist();
-        } else if self.index > N {
-            panic!("Generator was never seeded");
+        match self.index.cmp(&N) {
+            std::cmp::Ordering::Equal => self.twist(),
+            std::cmp::Ordering::Greater => panic!("Generator was never seeded"),
+            std::cmp::Ordering::Less => (),
         }
 
         const S: u32 = 7;