Review if both guide title and section title are needed

[ekes]

Review if the two title fields on the guide page are required; and if they are used. And if so if the UX when entering a new page could be improved - no need to repeat twice if they are the same for example.

The title is used for the page title. The section title for the title in the contents list.

[tanc]

Currently the two titles are used for different things. The title field is shown as an H2 title for the content (the H1 page title is taken from the guide overview). The section title is used as the text for the navigation links in the 'guide contents' block

[keelanfh]

I'd suggest that we don't require the Guide section title and fall back on the Title if the Guide section title is blank. I suggested similar for step-by-steps at localgovdrupal/localgov_step_by_step#71