support for add code block with stack exchange format in markdown edit buffer

[stardiviner]

I write answer with code block, but it does not have newline. Here is the screenshot of result.

[Malabarba]

Oh, I was under the impression that tripple backticks weren't valid code-blocks in SX format.

[stardiviner]

Oh, right. I forgot is. I will create a snippet by myself. close it now.