Fix fragment links on "How government works"

The IDs on the list of ministers appear to have been changed or
removed without these links being updated, so they no longer work.

Remove the trailing slash because GOV.UK issues a 301 redirect when
a path with a trailing slash is requested.
Merge pull request #1477 from alphagov/bugfix-fragment-links-how-government-works

Fix fragment links on "How government works"