Remove link for 'Personalization Semantics Content Module' on 1.3.5 Identify Input Purpose Understanding page and correct formatting

[snidersd]

On the Understanding page for 1.3.5 Identify Input Purpose, the link to 'Personalization Semantics Content Module' is no longer needed.

The link's current destination is: https://w3c.github.io/personalization-semantics/content/
The content had been changed and no longer addresses personalization semantics for content.

My recommendation is to remove it from the last paragraph.
In addition, the code snippets on this page are no longer formatted correctly.

[alastc]

I've updated the link with #3319, it looks like this is the most recent version: https://www.w3.org/TR/adapt-symbols/

I don't think we have any code-snippets as such. There are a few bits that could be wrapped in <code> tags, but it's a low priority thing. Feel free to re-open if you think it should be a higher priority, and/or can provide a PR.