Fix broken links

[hannahackermans]

Current State

On the Manifesto page, there is a table of contents that links to all the sections in the text. However, only the main sections work because they link to h3 elements. All subsections ‘link’ to regular text that has just been made to look like headings (see issue #59), so there is no target to skip to the right section.

Proposed changes to meet the success criteria

Once the heading levels are fixed, issue #59 , I think this will be fixed automatically. If this is not the case, we need to look at it again.