Add spacing for nested lists

[hannalaakso]

This PR:

• Add top margin for lists within lists
• Adds an example to frontend app
• Updates changelog

To review, view: /examples/typography

Trello card: https://trello.com/c/vuqWoun4/517-spacing-for-nested-lists-to-be-added-to-frontend

[NickColley]

In your example this seems to put a margin-top of 10px on the root level component, instead of just the nested lists, is this intended?

[NickColley]

[hannalaakso]

Good catch, not intended. Fixed now.

[NickColley]

In your amended commit, does this now only work for .govuk-list usage and not .govuk-prose?

[hannalaakso]

This should work for .govuk-list and for lists within .govuk-prose-scope. I've just added an example to /examples/prose-scope

[NickColley]

Sweet 👍

If anyone else is interested it gets mixed in here:

govuk-frontend/packages/globals/core/_prose-scope.scss

Line 35 in 0091fc8

.govuk-prose-scope ol {