Headings in episode 2 show anchors

[stelfrich]

Some of the headings in episodes/02-common-mistakes show their anchor tag in the rendered page.

It looks like rogue (?) backslashes might be the reason: https://github.com/datacarpentry/spreadsheets-socialsci/blob/9cdac552c336e3b2c89763151b5e7a1dbee4034c/episodes/02-common-mistakes.md?plain=1#L127

and

https://github.com/datacarpentry/spreadsheets-socialsci/blob/9cdac552c336e3b2c89763151b5e7a1dbee4034c/episodes/02-common-mistakes.md?plain=1#L153