While our Markdown formatting through marked.js technically allows '_'

to be unescaped in the middle of words without problems, it breaks

down in practice. There are bugs in marked.js that can cause '_' in

different parts of a string to be turend into emphasis.
Until that's fixed, or we move to server-side Markdown rendering, we'll

need to disable the escaping of '_' within words in order to prevent

these problems.

Tested a string that reproduced the problem (generated by Review Bot).
Unit tests pass.