Fix Table of Contents bug and add section label on hover for students

There are two components to this suggestion. First, there is a known bug affecting the Table of Contents view whereby instead of taking users to the heading of a particular section (as I'm sure it used to!), focus is typically on the first item in the section, with the heading not in view. We were presented with a use case from a student who could only see the heading of the subsequent section on-screen , causing confusion as to what they actually needed to read. Behaviour is inconsistent - a first click on the table of contents after loading the page is often not far off the mark, but subsequent clicks are less accurate. When working properly, the ToC is a really nice feature and a useful navigational aid, particularly on longer lists, so it would be good to see this known bug addressed.

Related to that, I only noticed when doing some testing the other day that student users do not see a label containing the section name when they hover over an item in the way users with editing permissions do. As this functionality already exists for editors (albeit alongside the Add resource/paragraph/section controls), I think it would make sense to add it for all users - it would be really helpful when looking at resources in longer sections.