Update source/manual/manage-sign-on-accounts.html.md
Update source/manual/manage-sign-on-accounts.html.md

Co-authored-by: Chris Ashton <2f515dc6e91662ff11b619335287254716cfcb8f@users.noreply.github.com>
alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs