Forum editor: add inline code

[stibbons]

The separate code block handling is great, but there are quite a few times when it's good to be able to refer to code-like things in the middle of a paragraph. Explaining function calls and referring to directories or commands are the places I use it most; just now I wanted to answer a question and include the KSP install directory in a sentence, like `~/Library/Application Support/Steam/SteamApps/common/Kerbal Space Program/` .

Ideally, I'd be able to select those inline statements and declare them as code. Setting them to a unispace font is one way to do it, but I'd prefer a separate code option that applies inline formatting to make those lines look similar to full-fledged code blocks.