fix clippy::range_plus_one

Author: hellow554

src/permutations.rs

@@ -185,7 +185,7 @@ where
                     let mut complete_state = CompleteState::Start { n, k };
 
                     // Advance the complete-state iterator to the correct point
-                    for _ in 0..(prev_iteration_count + 1) {
+                    for _ in 0..=prev_iteration_count {
                         complete_state.advance();
                     }
 
@@ -247,7 +247,7 @@ impl CompleteState {
                     return Known(0);
                 }
 
-                let count: Option<usize> = (n - k + 1..n + 1).fold(Some(1), |acc, i| {
+                let count: Option<usize> = ((n - k + 1)..=n).fold(Some(1), |acc, i| {
                     acc.and_then(|acc| acc.checked_mul(i))
                 });