`python3 refresh.py -r` has an error to deal with transferred meaning

[PiperLiu]

python3 refresh.py -r has an error to deal with transferred meaning, see codes:

in README.md：

### 其他
...
- x-的平方根『有转换$\sqrt{x}=x^{1/2}={(e^{\ln{x}}})^{1/2}=e^{\ln{x}/2}$和拟牛顿法两种数学推导，这里直接用二分查找』 [cpp](./vsc_leetcode/69.x-的平方根.cpp) 2021.1.9

after python3 refresh.py -r, it becomes:

### 其他
...
- x-的平方根『有转换$\\sqrt{x}=x^{1/2}={(e^{\\ln{x}}})^{1/2}=e^{\\ln{x}/2}$和拟牛顿法两种数学推导，这里直接用二分查找』 [cpp](./vsc_leetcode/69.x-的平方根.cpp) 2021.1.9

gotta find where the transferred meaning \ goes wrong.