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