In case we wanna compile locally, the following error occors with rustc:

```
❯ rustc 1.two_sum.rs
error: invalid character `.` in crate name: `1.two_sum`

error: aborting due to previous error
```

Fix misleading comments and trailing spaces while at it.

Changed LeetCode China domain

fix div-zero err in new problem's ac_rate

If the result of get_submissions() contains some invalid submissions, such as compile error,
it will cause get_submission() to get a non-integer value when fetching the runtime, which will cause a ValueError.

Signed-off-by: qun-wei.lin <[email protected]>

Fix ValueError in  get_submission() when doing int()