Ensure a blank line at end of document (#519)
Ensure a blank line at end of document (#519)

Currently, editing a page / document via the MarkdownEditor interface removes the blank line at the end of the file. This change ensures that a blank line is injected if it has been removed or doesn't exist otherwise.
jekyll/jekyll-admin,jekyll/jekyll-admin,jekyll/jekyll-admin,jekyll/jekyll-admin