chore: use iwyu on strings/**.cpp

strings/boyer_moore.cpp

@@ -42,12 +42,13 @@
  * @author [Stoycho Kyosev](https://github.com/stoychoX)
  */
 
-#include <cassert>   /// for assert
-#include <climits>   /// for CHAR_MAX macro
-#include <cstring>   /// for strlen
-#include <iostream>  /// for IO operations
-#include <string>    /// for std::string
-#include <vector>    /// for std::vector
+#include <cassert>    // for assert
+#include <climits>    // for CHAR_MAX
+#include <cstring>    // for size_t, strlen
+#include <iostream>   // for operator<<, basic_ostream, cout
+#include <string>     // for basic_string, string
+#include <vector>     // for vector
+#include <algorithm>  // for max
 
 #define APLHABET_SIZE CHAR_MAX  ///< number of symbols in the alphabet we use