DRYed up info box for code, added to Section.

Per [story 58611632](https://www.pivotaltracker.com/story/show/58611632).  Unlike the rest of the modals, the Section mustache template had the incorrect text for the info on code.

Since all the modals have the same text, I DRYed it up as well by passing the text to the template in the `code_info` variable.