There's a merged pull request on the void-packages repository

mdBook: update to 0.4.18
https://github.com/void-linux/void-packages/pull/36747

Description:
#### Testing the changes
- I tested the changes in this PR: **YES**

#### Local build testing
- I built this PR locally for my native architecture, (x86_64)

![Screenshot_20220418_134304](https://user-images.githubusercontent.com/45872139/163769145-69cc2174-9771-4da2-b28c-718c42f9826d.png)