Change occurrences of str.format to f-strings (#4118)

* f-string update rsa_cipher.py

* f-string update rsa_key_generator.py

* f-string update burrows_wheeler.py

* f-string update non_recursive_segment_tree.py

* f-string update red_black_tree.py

* f-string update deque_doubly.py

* f-string update climbing_stairs.py

* f-string update iterating_through_submasks.py

* f-string update knn_sklearn.py

* f-string update 3n_plus_1.py

* f-string update quadratic_equations_complex_numbers.py

* f-string update nth_fibonacci_using_matrix_exponentiation.py

* f-string update sherman_morrison.py

* f-string update levenshtein_distance.py

* fix lines that were too long

data_structures/binary_tree/non_recursive_segment_tree.py

@@ -49,7 +49,7 @@ class SegmentTree:
         :param arr: list of elements for the segment tree
         :param fnc: commutative function for combine two elements
 
-        >>> SegmentTree(['a', 'b', 'c'], lambda a, b: '{}{}'.format(a, b)).query(0, 2)
+        >>> SegmentTree(['a', 'b', 'c'], lambda a, b: f'{a}{b}').query(0, 2)
         'abc'
         >>> SegmentTree([(1, 2), (2, 3), (3, 4)],
         ...             lambda a, b: (a[0] + b[0], a[1] + b[1])).query(0, 2)

data_structures/binary_tree/red_black_tree.py

@@ -475,11 +475,13 @@ class RedBlackTree:
         from pprint import pformat
 
         if self.left is None and self.right is None:
-            return "'{} {}'".format(self.label, (self.color and "red") or "blk")
+            return f"'{self.label} {(self.color and 'red') or 'blk'}'"
         return pformat(
             {
-                "%s %s"
-                % (self.label, (self.color and "red") or "blk"): (self.left, self.right)
+                f"{self.label} {(self.color and 'red') or 'blk'}": (
+                    self.left,
+                    self.right,
+                )
             },
             indent=1,
         )

data_structures/linked_list/deque_doubly.py

@@ -20,8 +20,8 @@ class _DoublyLinkedBase:
             self._next = link_n
 
         def has_next_and_prev(self):
-            return " Prev -> {}, Next -> {}".format(
-                self._prev is not None, self._next is not None
+            return (
+                f" Prev -> {self._prev is not None}, Next -> {self._next is not None}"
             )
 
     def __init__(self):