Markdown rendering show softbreaks

### Describe the bug
On the web interface, lines that don't end with at least 2 spaces are not joined.

```shell
$ gh --version
gh version 0.9.0 (2020-05-26)
https://github.com/cli/cli/releases/tag/v0.9.0
```

### Steps to reproduce the behavior

If you run the following
command it your shell,
theses lines will be joined.

```shell
$ gh issue -R cli/cli view 1110
```