fix item numbering in chapter 8

[aharrison24]

Currently the numbered list in chapter 8 has the incorrect number against the 4th entry, because the markdown processor interprets it as a new list and starts the numbering at 1 again.

There doesn't seem to be any trivial way of marking up the list so that it starts at 4. discount doesn't seem to accept the {:start="4"} syntax that you can use with some other markdown processors.

This PR resorts to using some inline HTML to solve the problem. I suspect that might be unpalatable, so please feel free to summarily reject it! :-)

A different way of achieving more or less the same effect would be to use inline HTML to generate the list entry manually, like this:

&emsp;<span>4.</span> `free`: manually release/free a pair.</br> 

It works... but it's probably less robust to changes in the CSS.

🤷

[justinmeiners]

You're right that all these solutions sound terrible.
I think I found the hack I prefer:

   4. `free`: 

[aharrison24]

Ah OK, the span tags don't actually add anything in this case do they. That'll teach me for cargo-culting code without taking the time to actually engage my brain.

One   or 3x   looks like the least worst options!

[justinmeiners]

I didn't know about  . I'll give that a try.