Header permalinks do not always work

[carlfairclough]

It appears that some permalinks are not working.

To Reproduce
Steps to reproduce the behavior:

1. Visit https://ethereum.org/wallets/
2. Click the What is an Ethereum wallet, and which one should I use? permalink icon
3. See that nothing happens — the url is followed by %3F which is not in the heading id

Expected behavior
The link should go to the heading

[samajammin]

Mmmm I was a bit worried about this. I suspect the addition of markdown-it-attrs broke these header IDs since the use of bracket notation creates clashes.

We already use bracket notation on markdown headers to set explicit header ids (in order to keep anchor tags consistent across languages. More context on that feature can be found in the related issue.

I wonder the best way to resolve this. @carlfairclough do you feel the markdown-it-attrs package is necessary? Perhaps we could use a symbol other than brackets to generate these markdown header IDs.

[carlfairclough]

I'd be keen to keep markdown-it-attrs or roll-our-own version of it, otherwise people won't be able to leverage styles so easily. An alternative could be classy https://github.com/andrey-p/markdown-it-classy.

I'm unsure as to why manually adding IDs to each heading is necessary when it can be done automatically — why do anchor tags need to be consistent across languages, vs being relevant to the content on the page?

[samajammin]

I think I found a fix - PR coming shortly

[samajammin]

Re: the need for explicit IDs - does this issue not answer that question? Happy to explain if it doesn't.