Add visual placeholders for some C snippets.
Merge branch 'js/visual-placeholders-for-c-snippets' into visual-placeholders-for-c-snippets
Avoid indenting empty lines, and allow snip.mkline() to handle indentation.
Merge branch 'js/visual-placeholders-for-c-snippets'
Avoid indenting empty lines, and allow snip.mkline() to handle indentation.