Markdown soft line syntax inconsistency in Pull Request view

Summary

When viewing the markdown syntax for contributing.md from the pull request modal window, the soft lines are not respected and are instead shown as hard lines. When viewing the syntax render from the source, the soft lines are respected and rendered as expected.

Steps to Reproduce

1. Add file contributing.md to the root of your repository and push up.
2. Make changes to produce a pull request if one does not exist.
3. When viewing an open pull request, select the Contribution guidelines link from the top right of the PR.

Expected Results

In the modal window, soft line breaks should be shown as soft line breaks:

Actual Results

Soft lines are shown as hard lines breaking the content

Workaround

None at the moment.