FIx new Clippy warnings (TheAlgorithms#496)

Author: dsmurrow

src/graph/depth_first_search_tic_tac_toe.rs

@@ -274,7 +274,7 @@ fn append_playaction(
         return;
     }
 
-    let mut play_actions = opt_play_actions.as_mut().unwrap();
+    let play_actions = opt_play_actions.as_mut().unwrap();
 
     //New game action is scored from the current side and the current saved best score against the new game action.
     match (current_side, play_actions.side, appendee.side) {

src/math/pollard_rho.rs

@@ -178,8 +178,7 @@ pub fn pollard_rho_factorize(
         return result;
     }
     let mut to_be_factored = vec![number];
-    while !to_be_factored.is_empty() {
-        let last = to_be_factored.pop().unwrap();
+    while let Some(last) = to_be_factored.pop() {
         if last < minimum_prime_factors.len() as u64 {
             result.append(&mut factor_using_mpf(last as usize, minimum_prime_factors));
             continue;