Fix invalid indentation of strings with short lines

[aleksey-mashanov]

Every lines in option's discussion must be properly indented, even the short ones.

Checklist

• I've added at least one test that validates that my change is working, if appropriate
• I've followed the code style of the rest of the project
• I've read the Contribution Guidelines
• I've updated the documentation if necessary

[natecook1000]

@swift-ci Please test

[natecook1000]

Thanks @aleksey-mashanov! 🎉