MUNGE generated table of contents won't work when there's a symbol in the headline

If the title/headline contains symbols like `'` or `?`, the generated TOC link won't work. 

For example, the generated TOC link of the headline `### It doesn't work` will be `#it-doesn't-work`
but the link should be `#it-doesnt-work`; if the headline is `### How to do this?`, the link should be `#how-to-do-this` instead of `#how-to-do-this?`
