Update backtracking/magic_sequence.cpp

Co-authored-by: David Leal <halfpacho@gmail.com>

Author: Jxtopher

backtracking/magic_sequence.cpp

@@ -25,7 +25,6 @@
  * @brief Backtracking algorithms
  */
 namespace backtracking {
-
 /**
  * @namespace magic_sequence
  * @brief Functions for the [Magic sequence](https://www.csplib.org/Problems/prob019/) implementation