Update Leetcode 题解.md

独数题解中的调用回溯应该是backtracking(0, 0);  不是backtracking(i, 0);

docs/notes/Leetcode 题解.md

@@ -2316,7 +2316,7 @@ public void solveSudoku(char[][] board) {
             colsUsed[j][num] = true;
             cubesUsed[cubeNum(i, j)][num] = true;
         }
-        backtracking(i, 0);
+        backtracking(0, 0);
 }
 
 private boolean backtracking(int row, int col) {