Add timer to the label "@lc code=start "

[liusitan]

🚀 Feature Proposal

On the side of label @lc code = start, just like add submit to the side of the @lc code=end, an digital timer is added beside it. @lc code = start, "12:00"(mm:ss),restart, stop,resume

Motivation

This timer helps users to track their time usage on questions. It helps users to optimize their question-solving strategy.

Contribution

I wanna see the community feedback first, if everyone is happy with this addition, I will update the contribution as soon as possible.