Fix link render issue after page refreshing

[laysent]

Following markdown file illustrate how to reproduce this issue:

## repo

1. First click on the link shown [below](#internal-link)
2. Then refresh the page (url should end with `?id=repo`)
3. Link generated for internal links are wrong after refreshing,
`id` is added without removing existing one

    i.e. `?id=repo?id=repo`

    When clicking on these links, error will be thrown.

## internal link

Click [me](#repo)

Please makes sure these boxes are checked before submitting your PR, thank you!

• Make sure you are merging your commits to master branch.
• Add some descriptions and refer relative issues for you PR.
• DO NOT include files inside lib directory.