Table of contents links won't work if special characters present

[kieranjol]

I've noticed some links in the table of contents contain charaters like commas, slashes, brackets etc.
These result in non-functioning links. Examples include:

https://github.com/digipres/policies#james-hardiman-library,-nui-galway
https://github.com/digipres/policies#national-library-of-new-zealand-/-archives-new-zealand
https://github.com/digipres/policies#royal-pavillion-&-museums-trust--(brighton-and-hove-museums)

I only picked up on this when working on #2 and noticed that the preview had a few dead links.
I'm not sure what the best solution to this is!

[bitsgalore]

I fixed the 3 broken links in the following commit:

1f44d2d

Oddly this resulted in a complete rewrite of the top 120 lines, not entirely sure why, and this makes my changes quite difficult to spot.

EDIT: deleted commit which was a manual edit of the README; however this should be fixed at the level of the script that generates the Markdown from the CSV.

But there are many more broken links that could be fixed in a similar way. Some useful resources I found along the way:

• https://stackoverflow.com/questions/53171609/how-do-i-make-linked-references-to-sections-of-the-same-document-using-markdown
• https://stackoverflow.com/questions/57642572/github-markdown-link-containing-parentheses
• https://stackoverflow.com/questions/43885597/how-to-link-to-section-with-in-the-name-in-github-markdown

The key point is being aware how links and anchors are handled in Markdown, which is explained here. But it seems there are quite a few special cases, mostly related to particular characters.