Teach CSpell to ignore hash links

[julietrb1]

Our documentation uses syntax like {#server-configuration} to establish anchor links, but CSpell doesn't play well with this, and interprets the contents of such tags as spelling errors.

This commit ignores those tags by way of a regular expression to identify them. Hopefully this will mean a lot more passing PRs! 🥇

[steve-fenton-octopus]

Let's do it!

Note: I was gradually fixing these as they came up as these old bookmark links are long, use mixed case, and are generally not a nice thing to place in the address bar.

However, there are more impactful things to do, so we'll concede defeat on these (and fix them if we eyeball them).