Link to another note in the same book opens in a new tab in Chrome.

### Is this a hackmd.io issue?

- Yes, the bug happens on https://hackmd.io

### What's the problem

#### Current behaviour

1. Go to https://hackmd.io/@benabraham/book-example/
2. Open any link on the right side: link in “Go to Page B” etc.
3. Link opens in a new tab (most of the time).


###### Sources

- Book https://hackmd.io/0HWwfBvSR_eeA4f95qteZA
- Page A: https://hackmd.io/bC65cLJtT4iRtmCLxbIPKg
- Page B: https://hackmd.io/qoN4Ee9NSY-r9Adv4avV3g
- Page C: https://hackmd.io/uq8RHC3gQfWAb4QvqoUakQ

#### Expected behaviour

**I expect note to open in the same tab and in the right pane of the book**: the same it works in both the latest Firefox and Edge 18 because links have exactly the same URL as in the „book“.

#### Environment
I use HackMD on **Desktop**

- OS: Windows 10
- Browser: Chrome 64-bit
- Browser Version: 80.0.3987.149

This behavior is also visible in:

- OS: Linux Mint 19.3
- Browser: Chromium
- Browser Version: 80

and mobile

- OS: Android 9
- Browser: Chrome
- Browser Version: 80

#### Additional context

I tested it using a clean user profile (everything is default, no extensions except Google's default for offline Docs use).