Update 06-style-guide.md

[cleary3]

Adding figure dash, en dash, and em dash. Per swcarpentry/python-novice-inflammation#478 (comment)

[rgaiacs]

@cleary3 Thanks for the pull request. This need its own section. http://swcarpentry.github.io/lesson-example/06-style-guide/index.html should have four sections, for exemple

Keyboard Key

...

Keyboard Key Combination

...

Links

...

Dahses

On the lessons we make use of figure dash, en dash, and em dash following the ? style guide. Figure dash should be used for ... In the Markdown file, please use ... to insert the figure dash. En dash should be used for ... In the Markdown file, please use ... to insert the en dash. Em dash should be used for ... In the Markdown file, please use ... to insert the em dash.

My recommendation is require authors to use – and — because it make easy to find misuse of one dash.

Said that, I'm going to add this for discussion with other mentors. Thanks again for the pull request.

[cleary3]

Ah ha, now the requested change is clearer to me. Thanks!

Since you're wanting more discussion, I'll leave well enough alone for now. If you decided you do want the new section about Dashes, let me know and I can update the pull request.